Question

13. A car is moving with a uniform velocity of 30 m/s
It is stopped in 2 s by applying a force of 1500N through its brakes. Calculate : (a) the change in
momentum of car, (b) the retardation produced in
car, and (c) the mass of the car.
Ans.(a) 3000 kg m s^1 (b) 15 m s^-2 (c) 100 kg​

Answer 1

Answer:

(a) 3000 kg ms

(b) 15 m/s^2

(c) 100 kg

Step-by-step explanation:

As we all know that F = ma (ma is the absolute rate of change of momentum), so,

-1500N = ma (As force is being applied opp. to the direction of motion)

Here, m and a, both are unknown so let's first calculate a, then m

v = u+at

v = 0

0 = 30+2a

Transpose u to the other side

-30 = 2a

a = -15 m/s^2

F = ma

-1500N = -15m

m = 100 kg

Momentum (denoted by p≥) = mass*velocity

So, p≥ = 30*100

3000 kg ms