Question

A car and a lorry are moving with the same momentum, if the braking force is applied, then:
A) Car comes to rest in a shorter distance.
B) Lorry comes to rest in a shorter distance.
C) Both travel the same distance before coming to rest.
D) None of these.

Answer 1

The momentum is defined as the product of mass and velocity. The body with different mass and different velocities also can have the same momentum. Momentum is the tendency of the body to continue its motion.

Formula used: The formula of the momentum is given by,
$\Rightarrow p = m \times v$
Where momentum is p, the mass of the object is m and the velocity of the body is v.

Complete step by step solution:
It is given in the problem that the car and a lorry are moving with the same momentum, if the braking force is applied, then we need to tell which option is correct.
The formula of the momentum is,

$\Rightarrow p = m \times v$

Where momentum is p, the mass of the object is m and the velocity of the body is v.
So here the momentum is dependent on the mass and velocity and for the momentum to be constant the mass can be decreased and velocity can be increased and vice-versa.

The momentum is defined as the product of mass and velocity and it is given that the momentum of car and lorry is same and mass and velocity of the car and lorry are not same. Now since the mass of the lorry is more than the mass of the car and therefore the velocity of the lorry will be less and therefore when brake is applied then the lorry will come to rest faster. The lorry comes to rest in a shorter distance.

The correct answer for this problem is option B.

Note: Students are advised to understand and remember the formula of the momentum as it is a very important concept and also its formula should be remembered so as to solve these kinds of problems. The conservation of linear momentum allows it to fly as when the flue gases are coming out of the rocket and with the same momentum the rocket moves in the opposite direction.