Question

Example 4. If a body of mass 5 kg is moving along
a straight line with velocity 10 ms and acceleration
20 ms -2. Find its kinetic energy (KE) after 10 s.
Sol. Given, mass of the body, m = 5 kg​

Answer 1

Answer:

Given :

➡️ mass of the body = 5 kg

➡️ initial velocity = u = 10 m/s

➡️ acceleration of the body = 20 m/s ^2

➡️ time taken = 10 s

To find :

➡️ kinetic energy of the body (KE)

Solution :

To find the kinetic energy, we will have to find the velocity of the body(v) at t=10s.

according to the formula,

v = u+at, we can find the value of v by substituting the values of u,a and t

that is, v = (10+20×10)m/s

That is, v = 210m/s

Hence, the value of velocity of the body at 10s is 210 m/s.

We have, KE = 1/2 mv^2

That is, KE = (1/2 × 5 × 210 × 210)J

That is, KE = (22050 ×5)J

That is, KE = 110250 Joule

Hence, the kinetic energy of the body at t=10s is 110250J.