Question

the kinetic energy of an object mass (m) moving with a velocity of 5 m/ s is 25 j, what will be its kinetic energy when it's velocity bis double ? what will be it's kinetic energy when it's velocity is increased three times?

Answer 1

Given , k.e = 25j
V = 5m/s

Now , k.e = 1/2mv^2
Therefore , m = 25 × 2/25
m = 2 kg

When velocity is tripled ,
K.e = 1/2 × 2 × 5^3
= 125 J

Answer 2

$\sf\red{Given:-}$

Kinetic Energy ,KE = 25 J

Velocity ,V = 5m/s

$\sf\red{To\: Find:-}$

Kinetic energy when its velocity is increased three times.

$\sf\pink{Solution:-}$

Firstly we calculate the mass of the body . As we know that Kinetic Energy is the energy possess by body due to its motion.

• KE = 1/2mv²

Where

KE is the Kinetic Energy

m is the mass of the body

v is the final velocity

Substitute the value we get

$\implies$ 25 = 1/2×m× 5²

$\implies$ 25×2 = m × 25

$\implies$ 50 = m × 25

$\implies$ m = 50/25

$\implies$ m = 2 kg

Mass of the object is 2kg .

If the velocity of the object increase by three times .Then the new velocity is 3 × 5 = 15m/s

Now calculating the New kinetic Energy

• KE ' = 1/2mv²

Substitute the value we get

$\implies$ KE' = 1/2× 2 × 15²

$\implies$ KE' = 15×15

$\implies$ KE' = 225 J

Therefore, the new kinetic energy of the object is 225 Joules.