Question

A 2kg ball rolls down the hill. By the time it is at the bottom the balls kinetic energy is 25 J. What is the velocity at the bottom of the hill

Answer 1

Given:

• Mass of ball (m) = 2 kg

• Kinetic energy = 25 J

To be calculated:

Calculate the velocity(v) at the bottom of hill.

Solution:

As we know ,

$\bf\: Kinetic \: energy = \dfrac{1}{2} \times m \times {v}^{2}$

$\red \bigstar \bf \: putting \: the \: values$

$\rightarrow \: 25 = \dfrac{1}{2} \times 2 \times {v}^{2}$

$\rightarrow \: 25 \times 2 = 1 \times 2 \times {v}^{2}$

$\rightarrow \: 50 = 2 \times {v}^{2}$

$\rightarrow \: {v}^{2} = \cancel \dfrac{50}{2}$

$\rightarrow \: {v}^{2} = 25$

$\rightarrow \: v = \sqrt{25}$

$\rightarrow \: v = 5 \: m {s}^{ - 1}$