Question

A body of mass 5kg initially at rest is subjected to a force of 20N. What is the kinetic energy acquired by the body at the end of 10 sec...Please Help

Answer 1

Hi friend,

Force = mass × acceleration

A= F/m

a= 4 m/s ².

We know that,

K.e = 1/2 mv²

To find v:-

V= u+at

V= 0+40
V= 40 m/s.

K.E = 1/2 ×5×40×40

K.E =4000 J.

Hope this helped you a little!!!

Answer 2

Hi dear friend,

Thanks for asking this question.

Here is your answer : -

➡Mass of body = 5 kg
➡Force applied = 20 N
➡Time = 10 seconds

➡We know that,
↪Acceleration, A = Force/Mass
↪A = (20/5) m/s^2
↪A = 4 m/s^2

➡Also its known that,
↪Kinetic Energy = 1/2mv^2 (Mass,m ; v, speed)

➡We don't know 'v' ; To find 'v' ,
↪v = u + at
↪v = 0 + 40
↪v = 40 m/s

➡Now,
↪K.E. (Kinetic Energy) = 1/2mv^2
↪K.E. = 1/2 * 5 * (40)^2
↪K.E. = 1/2 * 5 * 1600
↪K.E. = 1/2 * 8000
↪K.E. = 4000

➡We also know that,
↪The unit we use for K.E. is Joule. It is represented by J.

➡So,
↪The final answer is = 4000 J


☑Hope my answer will be helpful to you dear.