Question

A boulder of mass 10 kg rolls over a cliff and reaches the beach below with a velocity of 15 m/s. Find:
a. the kinetic energy of the boulder as it lands;
b. the potential energy of the boulder when it was at the top of the cliff
c. the height of the cliff.​

Answer 1

Answer:

$hope \: its \: help \: u$

Explanation:

Answer:

Question

A boulder of mass 10 kg rolls over a cliff and reaches the beach below with a velocity of 15 m/s. Find:

a. the kinetic energy of the boulder as it lands;

b. the potential energy of the boulder when it was at the top of the cliff

c. the height of the cliff.

To find

a. the kinetic energy of the boulder as it lands;

b. the potential energy of the boulder when it was at the top of the cliff

c. the height of the cliff.

Formula used

Kinetic energy = mv²/2

Potential energy = m × g × h

Solution

➡️Kinetic energy = ½×mv²

➡️Kinetic energy = ½×10×15²

➡️Kinetic energy= 5 × 225 = 1125 Joule (J)

\small \fbox {The kinetic energy = 1125 J}

The kinetic energy = 1125 J

But when the body starts moving it converts Potential energy into kinetic energy. So , We know before reaching it has equal kinetic energy and potential energy.

Mgh = 1125 J

So, the potential energy of the boulder was on top is 1125 J

Now

➡️mgh = 10× 10 × h =1125 J

➡️mgh = 100h = 1125 J

➡️ h = 1125/100 = 11.25

\small \fbox {So the height of the body is 11.25 m}

So the height of the body is 11.25 m

\sf \underline {Hope it helps}

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