Question

For how long should a force of 100n act on body of 20 kg so that it acquires a velocity of 100m/s

Answer 1

Answer:

20sec

Explanation:

Given :

• Force (f)=>100 newton
• Mass (m) =>20kg
• Final velocity (v) =>100m/s

• Initial velocity (u)=> 0

To Find :

• Time (t)

Solution :

We know that

$\sf{}F=\dfrac{m(v-u)}{t}$

Put their values & solve the equation

$\sf{}100=\dfrac{20(100-0)}{t}\\ \\\sf{}100=\dfrac{2000-0}{t}\\ \\\sf{}100=\dfrac{2000}{t}\\ \\\sf{}\because t=20sec$

Therefore,it will take 20 sec

Answer 2

Explanation:

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