Question

A body of mass 5 kg is acted upon by a force 20 N for 7 seconds what will change in momentum will be?

Answer 1

Answer:

140 kg.m/s

Explanation:

We have,

• Mass of body, m = 5 kg
• Force applied, F = 20 N
• Time taken, t = 7 seconds

We have to calculate change in momentum.

Momentum is the product of mass and velocity. Change in momentum will be,

→ Change in momentum = Final momentum ― Initial momentum

→ ∆P = mv ― mu

Now, as we know that,

$\longrightarrow\boxed{ \bf{F = ma}}$

• F denotes Force

• m denotes mass

• a denotes acceleration

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

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

$\longrightarrow\sf{F = \dfrac{mv-mu}{t}}$

Substitute the values.

$\longrightarrow\sf{20 = \dfrac{mv-mu}{7}}$

$\longrightarrow\underline{\boxed{\sf{\blue{140 \; kg. ms^{-1} = mv-mu}}}}$

Therefore, change in momentum is 140 kg.m/s.