Question

The change in momentum of the ball of 0.5 Kg is 10 N
If its final velocity is 20m/s , its initial velocity is __________ m/s

Answer 1

GiveN :

• Mass (m) = 0.5 kg
• Change Momentum (Δp) = 10 kg m/s
• Final velocity (v) = 20 m/s

To FinD :

• Initial velocity

SolutioN :

We're given that mass of a ball is 0.5 kg, change in momentum is given as 10 kg m/s,and final velocity is 20 m/s. So, we have to find initial velocity.

Change in momentum = Final momentum - Initial momentum

Use formula,

⇒Δp = p1 - p2

Where,

• Δp is change in momentum.
• p1 is final momentum.
• p2 is initial velocity.

Putting Values :

⇒10 = mv - mu

⇒10 = m(v - u)

⇒10 = 0.5(20 - u)

⇒20 - u = 10/0.5

⇒20 - u = 20

⇒- u = 20 - 20

⇒- u = 0

⇒u = 0 m/s

∴ Initial velocity (u) is 0 m/s.

Answer 2

Given that ,

Mass of ball (m) = 0.5 kg

Change in momentum (ΔP) = 10 Ns

Final velocity (v) = 20 m/s

We know that , the change in momentum of a body is given by

ΔP = m(v - u)

Thus ,

10 = 0.5(20 - u)

20 = 20 - u

u = 0 m/s

$\sf \therefore{ \underline{The \: initial \: velocity \: of \: ball \: is \: 0 \: m/s}}$