Question

A 2 kg rock is rolling down a hill at a speed of 10m/s. What is the KE of the rock?

Answer 1

Answer:

m= 2 kg, v = 10m/s , using k.e.= 1/2mv^2

putting all values, k.e.= 100 joules

Answer 2

Answer:

Given: Rock is rolling down a hill having

mass = m = 2 kg

speed = v = 10 m/s

To find: Kinetic energy of rock KE =?

Step-by-step Solution:

KE

$= \binom{1}{2} m {v}^{2}$

$= \frac{1}{2} \times 2 \times 10 \times 10 \\ = 100 \: kg \: {m}^{2} {s}^{ - 2}$

Thus, Kinetic energy is 100 $kg \:{m}^{2} / {s}^{2}$.

But, 1 $kg\:{m}^{2} / {s}^{2}$= 1 J.

Therefore, the Kinetic Energy of the rock rolling down the hill is 100 J.