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2 years ago

The work-energy theorem states that the work done on an object is equal to a change in which quantity?

1 answer:

8 0

The work-energy theorem states that the net work done by the forces on an object equals the change in its kinetic energy.

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A rocket passes you at a speed of 0.85c, and you measure its length to be 35.0 m. What is its measured length when at rest?

viktelen [127]

Answer:

66.4 m

Explanation:

To solve the problem, we can use the length contraction formula, which states that the length observed in the reference frame moving with the object (the rocket) is given by

$L=L_0 \sqrt{1-(\frac{v}{c})^2}$

where

$L_0$ is the proper length (the length measured from an observer at rest)

v is the speed of the object (the rocket)

c is the speed of light

Here we know

v = 0.85c

L = 35.0 m

So we can re-arrange the equation to find the length of the rocket at rest:

$L_0 = \frac{L}{\sqrt{1-(\frac{v}{c})^2}}=\frac{35.0}{\sqrt{1-(\frac{0.85c}{c})^2}}=66.4 m$

8 0

3 years ago

What is the velocity of a car that traveled a total of 75 kilometers north in 1.5 hours?

swat32

The car's velocity is (distance + direction) / (time) =

(75 km-north) / (1.5 hrs) =

(75/1.5) (km-north/hr) = 50 km/hr north.

7 0

3 years ago

What do you call the theory that says gravitational attraction caused bits of matter to collapse, begin spinning, and eventually

Semenov [28]

The nebular hypothesis is the name of the theory where gravitational attraction caused bits of matter to collapse, eventually forming a solar system.
Hope this helps :)

7 0

3 years ago

A baseball hits a car, breaking its window and triggering its alarm which sounds at a frequency of 1210 Hz. What frequency (in H

IRINA_888 [86]

Answer:

The frequency of sound heard by the boy is 1181 Hz.

Explanation:

Given that,

Frequency of sound from alarm $f_{0} = 1210\ Hz$

Speed = -8.25 m/s

Negative sign show the boy riding away from the car

Speed of sound = 343

We need to calculate the heard frequency

Using formula of frequency

$f = f_{0}(\dfrac{v+v_{0}}{v-v_{s}})$

Where, $f_{0}$ = frequency of source

$v_{0}$ = speed of observer

$v_{s}$ = speed of source

$v$ = speed of sound

Put the value into the formula

$f=1210\times\dfrac{343+(-8.25)}{343-0}$

here, source is at rest

$f=1180.8\ Hz$

$f=1181\ Hz$

Hence, The frequency of sound heard by the boy is 1181 Hz.

8 0

3 years ago

Monochromatic light of a given wavelength is incident on a metal surface. however, no photoelectrons are emitted. if electrons a

kifflom [539]

If the object, ends up with a positive charge, then it is missing electrons. if it is missing electrons, then it must have been removed form the object during the rubbing process.

5 0

3 years ago