The kinetic energy of a javelin is 81 J, and its speed is 9.0 m/s. What is its mass?

A. 0.5 kg

B. 1.0 kg

C. 2.0 kg

D. 9.0 kg

Answers

Answer 1

Answer:

2 kg

Explanation:

K.E. = 1/2 m v^2

81   = 1/2  m (9^2)

1 = 1/2 m

m = 2 kg


Related Questions

1 point
8. A magnetic field of 30 T is directed perpendicular to the force of a coil
with an area of 0.36 m^2. Calculate the magnetic flux in the coil.

A)0.27 Wb
B)9.3 Wb
C)10.8 Wb
D)83.3 Wb

Answers

Answer:

the answer is. C.

Explanation:

[tex] 0.36 \times 30 = 10.8[/tex]

the solution

Where are active volcanoes most likely to found?
A.where rivers form
B where tectonic plate meet
C. Where oceans are deepest
D. Where land and water meet

Answers

Answer:

B. where tectonic plates meet

Explanation:

Most volcanoes occur near tectonic plate boundaries. For example, a large amount are found on the Ring of Firez connecting several plates.

0. 85 kg of lead, specific heat 128 J/kgC, is heated from 50 C to 95 C. How much heat energy did the sample absorb?

Answers

4896

0.85 x 45 x 128 = 4896

Change in energy = specific heat capacity x mass x change in temperature

The waves produced on the earth’s surface is called
(a) seismic wave
(b) longitudinal wave
(c) Micro wave
(d) Radio wave

Answers

Answer:

seismic wave

Explanation:

These waves are produced because of plate tectonicsThese helps are useful in measurements of earthquake.Used in seismograph.

How many feet will it take you to stop from 60 mph.

Answers

How many feet will it take you to stop from 60 mph


Answer- 180 feet

Hello~
Which of the following produces least friction?
(a) Sliding friction
(b) Rolling friction
(c) Composite friction
(d) Static friction​

Answers

Answer:

Rolling friction

Explanation:

When a object rolls down the all sides of object comes contact to under surface for very low timeFor which the friction decreases .

Option B is correct

Which change is an example of transforming potential energy to kinetic energy?

Answers

Answer:

Changing nuclear energy to radiant energy

Explanation:

   Conversely, potential energy is a type of energy stored in an object, which can be converted to kinetic energy.

   Nuclear energy is a type of potential energy because this energy is stored in the atomic nucleus.

In conclusion, changing nuclear energy to radiant energy is an example of transforming potential energy into kinetic energy.

Answer:

if you stand still, that's potential energy, and if you move that's kinetic energy.

Explanation:

When standing still, you aren't moving, which the potential energy now is enact, but if you move a muscle, even the tiniest one, it will cause a transformation into kinetic energy.

An object moving in the xy-plane is subjected to the force f⃗ =(2xyı^ 3yȷ^)n, where x and y are in m

Answers

The magnitude of the work done by force experience by the object is (2a²b + 3b²)J.

Work done by the force experienced  by the object

The magnitude of the work done by force experience by the object is calculated as follows;

W = f.d

where;

F is the applied force (2xyi + 3yj), where x and y are in metersd is the displacement of the object = (a, b)

The work done by the force is determined from the dot product of the force and the displacement of the object.

F = (2xyi + 3yj).(a + b)

W = (2abi + 3bj).(ai + bj)

W = (2a²b + 3b²)J

Thus, the magnitude of the work done by force experience by the object is (2a²b + 3b²)J.

The complete question is below:

The particle moves from the origin to the point with coordinates (a, b) by moving first along the x-axis to (a, 0), then parallel to the y-axis.

How much work does the force do?

Learn more about work done here: https://brainly.com/question/8119756

The total work done  for an object moving in the xy-plane is subjected to the force f⃗ =(2xyı^ 3yȷ^)n, where x and y are in m is 3ab N.

What is work done?

Work done is the force applied on a body to move it over a distance. Work done for inclined plane can be given as,

[tex]W=F\times d[/tex]

Here (F) is the magnitude of force and (d) is the distance traveled.

An object moving in the xy-plane is subjected to the force

[tex]\vec f =(2xy\hat i +3y\hat j)[/tex]

Here, x and y are in meter.

The particle moves from the origin to the point with coordinates (a, b) by moving first along the x-axis to (a, 0), then parallel to the y-axis.

(a) How much work does the force do?

For the first part, the particle moves along x-axis. It moves zero along x-axis. Thus, the force, as y=0.

[tex]W_1=\int\limits^a_0 {2xy\hat i} \, dx =0\\[/tex]

Now, when the object moves along y-axis,

[tex]W_2=\int\limits^a_0 {3y\hat j} \, dx \\W_2=3\int\limits^b_0 {y\hat j} \, dx\\W_2=3y(a-0)\\W_2=3ba\\W_2=3ab[/tex]

Total work done,

[tex]W=0+3ab\\W=3ab\rm\; N[/tex]

Thus, the total work done  for an object moving in the xy-plane is subjected to the force f⃗ =(2xyı^ 3yȷ^)n, where x and y are in m is 3ab N.

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Lightning always follows
(a) a thunder
(b) rain pour
(c) the easiest path
(d) a straight path

Answers

Answer:

a thunder

Explanation:

It's because the difference in speed of light and sound

Light has speed about 3×10^8m/sSound has speed 344m/s

So we hear thunder later

Answer:

C

Explanation:

Lightning is a giant spark. A single stroke of lightning can heat the air around it to 30,000 degrees Celsius This extreme heating causes the air to expand at an explosive rate. The expansion creates a shock wave that turns to a booming sound wave, better known as thunder. Thunder & lightning occur at roughly the same time, although u see the flash of lightning before u hear the thunder. This is because light travels much faster than sound.Lightning always follows the easiest path. Lightning strikes buildings or projecting objects such as trees, poles, wires or building than larger, flatter surfaces because the material in them provide easier paths to the ground than the other. The primary target of lightning are lone buildings.

Therefore, Thunder Follows The Easiest Part. And it is not (A) because Thunder Follows A Lightening Not Vice Versa.

which of these is an example of point source pollution

Answers

Answer:

the reaserch I did says that d is the correct answer

A man pushes a 8 kg object. A distance of 5. 0 m upward along a frictionless slope that makes an angle of 30° with the horizontal. His force is parallel to the slope. If the speed of the object decreases at a rate of 1. 5 m/s, then the work done by the man is:​

Answers

Answer:

is 200 J

Explanation:

hope this is the right answer

Which law of Newton explains why it's harder to stop a truck than a car moving at the same speed.

Answers

Answer:

Inertia

Explanation:

Inertia is also the reason that it is harder to stop a loaded truck going 55 miles per hour than to stop a car going 55 miles per hour. The truck has more mass resisting the change of its motion and therefore, more inertia.

How many electrons will it take to give a hot wired fence a charge of 3.5 X 10^6 C?

Answers

Answer:

Q = N e     where N e is the number of electrons required to produce charge Q

N = Q / e = 3.5E6 C / 1.6E-19C = 2.2E25   = 2.2 X 10^25    electrons

Answer:

3.5 million C

Explanation:

One source error is __________, and one of its solutions is having a lie scale inserted into the assessment. a. social desirability bias b. deliberate deception c. response bias d. response set please select the best answer from the choices provided a b c d

Answers

One source error is deliberate deception and one of its solutions is having a lie scale inserted into the assessment.]

What is the error?

An error is a mistaken or erroneous action. In some contexts, an error is interchangeable with a mistake.

The discrepancy between the calculated value and the correct value is referred to as an "error" in statistics.

When a person is completely aware of what they are doing, they are engaging in deception. They are concealing the truth and making a deliberate decision to tell someone something that is false.

When describing a magic trick, such as a sleight of hand, the term deception can also be used.

When there are repetitive questions that ask the same questions over and over with different formats to check if the responses are constant over time, lie scales are utilized.

Hence one source error is deliberate deception and one of its solutions is having a lie scale inserted into the assessment.

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A solid sphere is released from the top of a ramp that is at a height
h1 = 2.20 m.
It rolls down the ramp without slipping. The bottom of the ramp is at a height of
h2 = 1.87 m
above the floor. The edge of the ramp is a short horizontal section from which the ball leaves to land on the floor. The diameter of the ball is 0.14 m.
a.) Through what horizontal distance d, in meters, does the ball travel before landing?
b.) How many revolutions does the ball make during its fall?

Answers

Hi there!

We can use the work-energy theorem and apply it to this situation.

At the top of the ramp, the ball only has gravitational potential energy, and at the bottom of the ramp, the ball has BOTH translational and rotational kinetic energy.

We must use the following equations:
[tex]GPE = mgh \\KE_T = \frac{1}{2}mv^2\\\\KE_R = \frac{1}{2}I \omega^2[/tex]

m = mass of sphere (kg)
g = acceleration due to gravity (m/s²)

h = height of ramp (m)

v = final velocity (m/s)
I = Moment of Inertia (kgm²)

ω = angular velocity (rad/sec)

Since:
[tex]E_i = E_f\\\\mgh = \frac{1}{2}mv^2 + \frac{1}{2}I\omega ^2[/tex]

In order to make things easier, since the ball is not slipping, we can relate angular velocity to translational velocity:
[tex]\omega = \frac{v}{r}[/tex]

Also, recall the equation for the moment of inertia for a solid sphere:
[tex]I = \frac{2}{5}mr^2[/tex]

We can use these to simply our equation:
[tex]KE_R = \frac{1}{2}(\frac{2}{5}mr^2)(\frac{v}{r})^2 = \frac{1}{5}mv^2[/tex]

Now, we can rewrite the equation and solve for 'v'.

[tex]mgh = \frac{1}{2}mv^2 + \frac{1}{5}mv^2\\\\mgh = \frac{7}{10}mv^2\\\\v = \sqrt{\frac{10gh}{7}} = \sqrt{\frac{10(9.8)(2.2 - 1.87)}{7}} = 2.149\frac{m}{s}[/tex]

a)

We can begin by solving for the time taken for the ball to land on the ground. The ball only has a horizontal velocity, so this is essentially a free-fall situation. Use the rearranged kinematic equation:
[tex]t = \sqrt{\frac{2h}{g}} = \sqrt{\frac{2(1.87)}{9.8}} = .6178 s[/tex]

Now, use the following equation to solve for horizontal distance given horizontal velocity and time:
[tex]d_x = v_x t\\\\d_x = 2.149 * .6178 = \boxed{1.328 m}[/tex]

b)
We can use the previously-stated relationship between translational and angular velocity to solve for the angular velocity.

[tex]\omega = \frac{v}{r}[/tex]
It is given that the diameter is 0.14 m, so the radius is 1/2th the diameter, or 0.07 m.

Solve for the angular velocity:
[tex]\omega = \frac{2.149}{0.07} = 30.706 \frac{rad}{sec}}[/tex]

Using the above fall time and dimensional analysis to convert from rad/sec to revolutions, we can solve for the # of revolutions made by the ball:
[tex]\frac{30.706rad}{sec} * .6178 sec * \frac{1 rev}{2\pi rad} = \boxed{3.019 rev}[/tex]

Which is the destructive interference formula for diffraction grating problems? dsin = dcos = dcos = n dsin = n.

Answers

The destructive interference formula for diffraction grating problems is [tex]d sin \theta = (n+\frac{1}{2})\lambda[/tex].

What is the definition of destructive interference?

Destructive interference happens when the maxima of two waves are 180° out of phase a positive displacement of one wave is canceled exactly by a negative displacement of the other wave.

The formula for brighter patches resulting from constructive interference and darker patches resulting from destructive interference in a diffraction grating is:

[tex]\rm d sin \theta = n \lambda[/tex]

The grating spacing is denoted by d, the angle of light is denoted by a the fringe order is denoted by n, and the wavelength is denoted by [tex]\rm \lambda[/tex].

The destructive interference formula is now based on the fact that destructive interference occurs between the fringes.

Hence the destructive interference formula for diffraction grating problems is [tex]d sin \theta = (n+\frac{1}{2})\lambda[/tex].

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Answer:

A. dsin  =

Explanation:

Which kind of wave moves back and forth along the direction of the wave?.

Answers

The kind of wave it is Longitudinal

Arm ab has a constant angular velocity of 16 rad/s counterclockwise. At the instant when theta = 60

Answers

The linear acceleration of collar D when θ = 60° is - 693.867 inches per square second.

How to determine the angular velocity of a collar

In this question we have a system formed by three elements, the element AB experiments a pure rotation at constant velocity, the element BD has a general plane motion, which is a combination of rotation and traslation, and the ruff experiments a pure translation.

To determine the linear acceleration of the collar ([tex]a_{D}[/tex]), in inches per square second, we need to determine first all linear and angular velocities ([tex]v_{D}[/tex], [tex]\omega_{BD}[/tex]), in inches per second and radians per second, respectively, and later all linear and angular accelerations ([tex]a_{D}[/tex], [tex]\alpha_{BD}[/tex]), the latter in radians per square second.

By definitions of relative velocity and relative acceleration we build the following two systems of linear equations:

Velocities

[tex]v_{D} + \omega_{BD}\cdot r_{BD}\cdot \sin \gamma = -\omega_{AB}\cdot r_{AB}\cdot \sin \theta[/tex]   (1)

[tex]\omega_{BD}\cdot r_{BD}\cdot \cos \gamma = -\omega_{AB}\cdot r_{AB}\cdot \cos \theta[/tex]   (2)

Accelerations

[tex]a_{D}+\alpha_{BD}\cdot \sin \gamma = -\omega_{AB}^{2}\cdot r_{AB}\cdot \cos \theta -\alpha_{AB}\cdot r_{AB}\cdot \sin \theta - \omega_{BD}^{2}\cdot r_{BD}\cdot \cos \gamma[/tex]   (3)

[tex]-\alpha_{BD}\cdot r_{BD}\cdot \cos \gamma = - \omega_{AB}^{2}\cdot r_{AB}\cdot \sin \theta + \alpha_{AB}\cdot r_{AB}\cdot \cos \theta - \omega_{BD}^{2}\cdot r_{BD}\cdot \sin \gamma[/tex]   (4)

If we know that [tex]\theta = 60^{\circ}[/tex], [tex]\gamma = 19.889^{\circ}[/tex], [tex]r_{BD} = 10\,in[/tex], [tex]\omega_{AB} = 16\,\frac{rad}{s}[/tex], [tex]r_{AB} = 3\,in[/tex] and [tex]\alpha_{AB} = 0\,\frac{rad}{s^{2}}[/tex], then the solution of the systems of linear equations are, respectively:

Velocities

[tex]v_{D}+3.402\cdot \omega_{BD} = -41.569[/tex]   (1)

[tex]9.404\cdot \omega_{BD} = -24[/tex]   (2)

[tex]v_{D} = -32.887\,\frac{in}{s}[/tex], [tex]\omega_{BD} = -2.552\,\frac{rad}{s}[/tex]

Accelerations

[tex]a_{D}+3.402\cdot \alpha_{BD} = -445.242[/tex]   (3)

[tex]-9.404\cdot \alpha_{BD} = -687.264[/tex]   (4)

[tex]a_{D} = -693.867\,\frac{in}{s^{2}}[/tex], [tex]\alpha_{BD} = 73.082\,\frac{rad}{s^{2}}[/tex]

The linear acceleration of collar D when θ = 60° is - 693.867 inches per square second. [tex]\blacksquare[/tex]

Remark

The statement is incomplete and figure is missing, complete form is introduced below:

Arm AB has a constant angular velocity of 16 radians per second counterclockwise. At the instant when θ = 60°, determine the acceleration of collar D.

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Collette is twisting a screwdriver. The scredriver has a handle with a radius of 18 mm. If she is exerting a force of 14 N, how much torque is she causing? PLEASE HELPPP!!!!

A. 25 Nm
B. 0.25 Nm
C. 1.3 Nm
D 0.75 Nm

Answers

Radius=18mm=1.8cm=0.018mForce=14N

Torque:-

[tex]\\ \rm\Rrightarrow \tau =14(0.018)[/tex]

[tex]\\ \rm\Rrightarrow \tau=0.25Nm[/tex]

option B

If Earth had no greenhouse gases, the planet would be

Answers

Earth would be an icy wasteland if greenhouse gases were not present. Greenhouse gases keep our planet livable by retaining some of the Earth's heat energy, preventing it from escaping into space. The greenhouse effect refers to the trapping of heat.

Which characteristic is the same for every color of light in a vacuum?.

Answers

In a vacuum all colors of light travel with same speed and this is the reason a white ray travels through the vacuum without going through any dispersion..

What is speed?

Speed of light is the distance per time light waves propagate through different materials. The value for the speed of light in a vacuum is now defined as exactly 299,792,458 metres per second.

Therefore, In a vacuum all colors of light travel with same speed and this is the reason a white ray travels through the vacuum without going through any dispersion

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Blue, green, and red are _______ colors of light.

Answers

Answer:

the answer is white they combine to give white

Answer:

they are primary colors of light.

(pls don't delete this answer because I am just trying to help)

Radio galaxies have twin radio jets that emanate from a central core. An astronomer

finds a radio galaxy whose frequency is 20 MHz. What wavelength of radio waves

does the galaxy emit?

Answers

The wavelength of the radio waves emitted by the radio galaxies which have twin radio jets that emanate from a central core is determined as 15 m.

Wavelength of the radio waves

The wavelength of the radio waves is the distance traveled by the radio waves. The magnitude of the wavelength is determined from the ratio of speed of radio waves to the frequency of the radio waves.

v = fλ

where;

v is the speed of the radio wavesf is the frequency of the radio wavesλ is the wavelength of the radio waves

Radio wave is an example of electromagnetic radiation, and it travels at the same speed as light (3 x 10⁸ m/s).

λ = v/f

λ = (3 x 10⁸ ) / (20 x 10⁶)

λ = 15 m

Thus, the wavelength of the radio waves emitted by the galaxy is 15 m.

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A wave pulse on a spring is 5.40 cm high and oriented upward. This pulse meets another pulse of the same shape which is 1.10 cm high but oriented downward.
At the moment when the two pulses come together, what is the amplitude of the resulting pulse? Note: if the pulse is oriented upward, make its amplitude positive. If it is oriented downward, make its amplitude negative.

Answers

The resulting positive amplitude of the two waves after the superimposition is 4.30 cm.

Amplitude of the waves

The amplitude of the waves is the maximum displacement of the wave. This is the vertical position of the wave measured from the zero origin.

After the superimposition of the two similar waves, the resulting amplitude will be less than the initial amplitude of the wave with the highest vertical height since the superimposition creates destructive interference.

Resulting amplitude of the two waves is calculated as;

A = 5.4 cm - 1.10 cm

A = 4.30 cm

Thus, the resulting positive amplitude of the two waves after the superimposition is 4.30 cm.

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When we harness energy using photovoltic cells in a large panel on the roofs of buildings, we are using
power

A solar

B geothermal

C wind

D biomass

Answers

Answer:

solar

Explanation:

this is a form of solar panel

How much force does the astronaut exert on his chair while accelerating straight up at 10.0 m/s2m/s2

Answers

Answer:

M a = Fc -M g

Use up as positive - a is the acceleration upwards

Fc = M (a + g)       force exerted by chair

Fc = 19.8 M m/s^2      where M is the mass of the astronaut

The force exerted by the astronaut accelerating straight up with an acceleration of 10 m/s² is m/5 Newton.

What is force?

If you want to accelerate a body of mass 'm' with acceleration 'a' than a force of magnitude given by the product of mass and acceleration is needed.

Given is an astronaut accelerating straight up with an acceleration of 10 m/s².

Since the astronaut is moving in upward direction, the resultant resultant force is in upward direction. Now, assume that the force exerted by the astronaut on the chair is F[A].  The normal reaction force on the astronaut will also be same. Mathematically -

F[N] = F[A]

Now, we can write the resultant normal reaction force as -

ma - mg = F[N]

F[N] = m(a - g)

F[N] = m(10 - 9.8)

F[N] = m(0.2)

F[N] = m/5

F[A] = F[N] = m/5

where m is the mass of astronaut.

Therefore, the force exerted by the astronaut accelerating straight up with an acceleration of 10 m/s² is m/5 Newton.

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Please help asap its for anatomy

explain the basic mechanical process through which micturition occurs, including an explanation of why someone might not be able to "hold it in" any longer if they wait too long to urinate and why it might be harder for older people to hold their urine for a long time

Answers

The smooth muscle in the wall of the bladder when stretched triggers the micturition reflex (urination).

What is a Bladder?

This is defined as a lined layers of muscle tissue that stretch to hold urine in organisms.

In older people the elasticity of the bladder is reduced which is why it makes it harder for them to hold urine for a long time.

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A rocket is launched straight up with a velocity of 7.59. What would be the velocity when it lands?

Answers

Answer:

the same as the initial launch velocity (7.59 m/s)

Explanation:

vf^2 = vi^2 + 2ad

d = displacement = 0, so vf^2 = vi^2, so vf = vi = 7.59m/s

What is the speed of a wave that has a frequency of 440 Hz and a wavelength of 0.78 m? O A. 564 m/s m B. 0.003 m/s C. 343 m/s D. 0.002 m/s​

Answers

Explanation:

velocity = frequency × wave length

velocity = 440 × 0.78

velocity = 343 m/sec

can you please mark my answer brainliest ♥️

Henri becquerel shared a nobel prize for his work in discovering what?.

Answers

Spontaneous Radio activity
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