Question

Calculate the impulse necessary to stop a 1500kgcar travelling at 90km/hr?

Answer 1

Impulse = ∆p I.e. change in momentum

So amount of impulse required
=final momentum - initial momentum
=1500 × 0 - 1500kg × 25m/s
=0 - 37500
= –37500Ns

HOPE IT HELPS..... :-)

Answer 2

Given:

Mass of the car = 1500 kg

Initial velocity (u) of the car = 90 km/h

To find:

Impulse

Explanation:

• Impulse, in simple is small change in momentum that lasts for only a short time but creates large amount of momentum change.
• For example, Impulse is seen while playing cricket, when the batsmen hits the ball, at the contact of bat and ball a for a brief amount of time impulse is generated which is so strong to easily deliver a slow ball out of the boundary.
• Mathematically, impulse is the change in momentum only hence it SI unit is the same as that of momentum that is kg m/s.

                   Impulse (J) = m(v -u)

Solution:

We have been given in the question that a car travelling at 90 km/h has to be brought to rest . Hence, Final velocity of the car will be 0 km/h.

Now, we have,

u = 90 km/h = 90 ×5/18 = 25 m/s

v = 0 km/h = 0 m/s

m = 1500 kg

Substituting the given values in the given equation, we get

J = 1500(0 -25)

  = - 37500 kg m/s

Final answer:

Hence, the impulse required to stop the car is -37500 kg m/s.