Question

. Find the increase in kinetic energy of a body of mass 600 gram when its speed increases from 2 metre

per second to 4 metre per second​

Answer 1

Answer :

The increase in Kinetic Energy = 3.6 J

Explanation :

Given,

• mass of the body, m = 600 grams
• it's speed increases from 2 m/s to 4 m/s

To find,

• the increase in kinetic energy of the body

Solution,

⇒ mass of the body,

m = 600/1000 kg

m = 0.6 kg

We know that,

Kinetic energy of a body =  $\bf \frac{1}{2}mv^2$

⇒ When v = 2 m/s

 Kinetic energy,

     $\sf{KE_1=\frac{1}{2}(0.6)(2^2)} \\\\ KE_1=0.3 \times 4 \\\\ KE_1=1.2 \ J$

⇒ When v = 4 m/s

 Kinetic energy,

    $\sf{KE_2=\frac{1}{2}(0.6)(4^2)} \\\\ KE_2=0.3 \times 16 \\\\ KE_2=4.8 \ J$

The increase in Kinetic Energy

       $\sf \triangle KE=KE_2-KE_1 \\\\ \triangle KE =4.8-1.2 \\\\ \triangle KE =3.6 \ J$

∴ The increase in Kinetic Energy = 3.6 Joule