Question

A car of 1000 kg moves with a velocity of 10m/s.On applying brakes it comes to rest in 5 s.Then what are its initial momentum and final momentum? ​

Answer 1

• Mass of the car, m = 1000 kg

• Initial velocity of the car, u = 10 m/s

• Since the brake is applied , the final velocity , v = 0

• Time when it comes to rest, t = 5 s

MOMENTUM

• Momentum is equal to the product of the mass and velocity of the object.

• It is a vector quantity having both magnitude and direction.

• Momentum , p = mv

INITIAL MOMENTUM

$p = m \times u \\ \\ p = 1000 \times 10 \\ \\ p = 10000 \: kg \: \frac{m}{s}$

Initial momentum of the car before the application of brake is 10000 kgm/s.

FINAL MOMENTUM

$p = m \times v \\ \\ p = 1000 \times 0 \\ \\ p = 0$

The final momentum when the car is stopped is zero.

Answer 2

Answer:

Given :-

• A car of 1000 kg moves with a velocity of 10 m/s. On applying brakes it comes to rest in 5 seconds.

To Find :-

• Initial momentum
• Final momentum

Formula Used :-

❶ To find initial momentum,

★ Initial momentum = Mass × Initial Velocity ★

❷ To find final momentum,

★ Final momentum = Mass × Final Velocity ★

Solution :-

Given :

• Mass = 1000 kg
• Initial Velocity = 10 m/s
• Final velocity = 0 m/s
• Time = 5 seconds

❶ To find initial momentum,

⇒ Initial momentum = 1000 kg × 10 m/s

➠ Initial momentum = 10000 kg m/s

∴ The initial momentum is 10000 kg m/s .

❷ To find final momentum,

↦ Final momentum = 1000 kg × 0 m/s

➦ Final momentum = 0 kg m/s

∴ The final momentum is 0 kg m/s .