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

Answer

• Initial momentum = 10000 kg m/s
• Final momentum = 0 kg m/s

Explanation

Given

• Mass = 1000 kg
• Velocity = 10 m/s
• Time = 5 sec
• Final Velocity = 0 m/s

To Find

• Initial Momentum?
• Final Momentum?

Solution

Momentum of a body is given by,

Momentum = Mass × Velocity

Initial Momentum

➝ Mass × Velocity

• Mass = 1000 kg
• Initial Velocity = 10 m/s

Substituting the values,

➝ Momentum = Mass × Initial Velocity

➝ Momentum = 1000 × 10

➝ Momentum = 10000 kg m/s

Final Momentum

➝ Mass × Velocity

• Mass = 1000 kg
• Final Velocity = 0 m/s

Substituting the values,

➝ Momentum = Mass × Final Velocity

➝ Momentum = 1000 × 0

➝ Momentum = 0 kg m/s

Answer 2

Given :-

• Mass = 1000 kg
• Initial velocity = 10 m/s
• Time taken = 5 sec

Brakes are applied , so

• Final velocity = 0 m/s

To find :-

Initial and final momentum

Formula used :-

Momentum [ p ] = Mass [ m ] × Velocity [ v ]

Solution :-

So, Initial momentum =

☯ Mass × initial velocity

→ 1000 kg × 10 m/s

→ 10,000 kg m/s

Final momentum =

☯ Mass × final velocity

→ 1000 kg × 0 m/s

→ 0

Here,

Initial velocity = 10,000 kg m/s

Final velocity = 0

Thank You !!