Question

If a constant force of 1N acts on a body for 2 mints the change in momentum of a body will be
A 2 N.s
B 20 N.s
C 120 N.s
D 1200 N.s

Answer 1

Given

Force on body = 1N

Time given = 2 minutes.

To find

Change in momentum of body

Solution

Here, time (t) = 2 minutes.

➥ Time (t) = (2 × 60)s

➥ Time (t) = 120 s

We know that,

➝ Impulse = Force × Time

Putting values we get :

⇒ Impulse = 1N × 120s

⇒ Impulse = 120N.s

Now we know that, impulse means product of force & elapsed time. Impulse applied on a body produces change initial momentum of body.

Main formula is :

∆p = F × ∆t

Here, ∆p means change in momentum & ∆t means elapsed time that force acts on body.

That means, impulse on a body means change in momentum of body.

Therefore, impulse = Change in momentum

Hence,

Change in momentum of body = C. 120 N.s

Answer 2

Given :-

A constant force of 1 N acts on a body for 2 mins.

• Force = 1 N

• Time = 2 mins = 120 s

To find :-

The change in momentum of the body.

Solution :-

We know,

Impulse = Force*Time

By putting the known values in the formula, we get :

Impulse = 1*120

⇒ Impulse = 120 N.s

« Impulse applied on a body produces change in the initial momentum of the body.

We know,

◙ $\Delta$P = F * $\Delta$t

○ (Index - $\Delta$P represents the change in momentum and

So, we conclude that, impulse is nothing but the change in momentum.

$\Delta$P = Impulse

⇒120 N.s = $\Delta$P

∴ So, the change in momentum is (c) 120 N.s.