Question

For how long a force of 100N acts on a body of 20kg at rest ,so that it acquires a velocity of 100m/s

Answer 1

Answer:

20 seconds

Explanation:

m=20kg

F=100N

u=0m/s

v= 100m/s

According to Newtons' Second law of Motion

F=ma

F=m(v-u/t)

100=20(100-0/t)

100=2000/t

t=2000/100

t=20s

Answer 2

Answer:

First we will use the equation F=ma

100 = 20×a (F=100N, m=20 kg )

Therefore, a =100/20 =5m/s^2

The body was initially at rest

So, u=0m/s

v=100m/s

Now we will use the first equation of motion

v = u + at

100 = 0 +5×t

100 = 5t

t = 20 sec