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3 years ago

If a rock falls for 5 seconds near the surface of the earth and with no air friction, it will reach a velocity of

Physics

1 answer:

sukhopar [10]3 years ago

3 0

Answer: -49m/s.

Explanation:

As the rock only falls, we will assume that the initial vertical velocity is zero.

We neglect the air friction, so the only force acting on the rock is the gravitational force, this means that the acceleration is -g = -9.8m/s^2.

Then we can write:

a(t) = -9.8m/s^2

To write the velocity of the rock, we must ingrate over time and get:

v(t) = (-9.8m/s^2)*t + v0

where v0 is the initial vertical velocity, and as we said above, v0 = 0m/s

Then the vertical velocity as a function of time is:

v(t) = (-9.8m/s^2)*t

Now, the question is:

"...If a rock falls for 5 seconds near the surface of the earth and with no air friction, it will reach a velocity of..."

Then we need to evaluate the velocity equation in t = 5 seconds.

v(5s) = (-9.8m/s^2)*5s = -49m/s.

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4 years ago

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3 years ago

One horse is pulling a 755 kg sled straight ahead applying a force of 1988 N. If the acceleration of the sled is 1.36 m/s2, what

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The coefficient of kinetic friction is 0.13

Explanation:

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$\sum\overrightarrow{F}=m\overrightarrow{a}$ (1)

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