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

According to the Question

It is given that car of 1000 kg moves with a velocity of 10m/s. On applying brakes it comes to rest in 5s.

We have to calculate the its initial momentum and final momentum?

Firstly we calculate the Initial momentum of the car .

Calculating Initial momentum :

• Initial Momentum = Mass × Initial velocity.

Put the given value we get

↠ Initial momentum = 1000 × 10

↠ Initial momentum = = 10000 Kgm/s

• Hence, the initial momentum of the car is 10000 Kgm/s.

____________________________

Now, calculating the Final momentum of the car .

As it is given that brakes are applied on car and it stops after 5s . So, its final velocity is 0m/s

Calculating Final Momentum :

• Final Momentum = Mass × Final Velocity

Put the given value we get

↠ Final momentum = 1000×0

↠ Final momentum = 0 Kgm/s

• Hence, the final momentum of the car is 0 Kgm/s.

Answer 2

$\large\underline{\underline{\text{Question:}}}$

• 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?

$\large\underline{\underline{\text{Solution:}}}$

Finding Initial momentum,

• $\text{Mass of car (M) = 1000kg}$

And,

• $\text{Initial velocity }{(u) = 10m {s}^{ - 1} }$

As we know that,

• $\boxed{ \text{Initial momentum} = M u }$

Let substitute the given values,

$\cdot \cdot \cdot \longrightarrow \text{Initial momentum} = 1000kg \times (10m {s}^{ - 1} )$

We get,

$\cdot \cdot \cdot \longrightarrow \boxed{\text{Initial momentum} = 10000kg m {s}^{ - 1} }$

Therefore,

• The Initial momentum of car is 10000kgm/s.

Finding Final momentum,

• $\text{Final velocity }{(u) = 0m {s}^{ - 1} }$

As we know that,

• $\boxed{ \text{Final momentum} = M v }$

Let substitute the given values,

$\cdot \cdot \cdot \longrightarrow \text{Final momentum} = 1000kg \times (0m {s}^{ - 1} )$

We get,

$\cdot \cdot \cdot \longrightarrow \boxed{\text{Final momentum} = 0kgm {s}^{ - 1} }$

Therefore,

• The final momentum of car is 0kgm/s.

$\large\underline{\underline{\text{Required Answer:}}}$

• The Initial momentum and final momentum of car are 10000kgm/s and 0 respectively.