Question

A force of 12N acts on an  object of mass of 4kg in the state of rest for 3s. Calculate the kinetic energy acquired by the  object.​

Answer 1

Answer:

we know that, F=m×a

given that,

f=12n

m=4kg

t=3s.

therefore u=0

a=v-u/t=F/m

12/4=3m/s2

v=u+at

v=0+3×3=9m/s

kE=1/2mv2

ke=1/2×4×(9)2

K.E=2×81=162j.

hope it helpful for u

Answer 2

Answer:

Kinetic energy acquired by the object.

Explanation:

Given:

F = 12N

m = 4 kg

t = 3s

Using

v= u +at   ....(1)

Calculation:

Here, initial velocity ,u =0 and acceleration is calculated by Newton's second law of motion.

F = ma

12 =4×a

a=3 m/s²

Putting these values in equation (1) we get;

v = 0+3×3

v = 9 m/s

now as we know that Kinetic energy is equal to

K.E. =$\frac{1}{2}$mv²

K.E.=$\frac{1}{2}$×4×9²

K.E. =162 joules.

Hence, Kinetic energy is equal to 162 joules.