Question

Pose a real life problem situation, where you need mechanical physics to solve it. The problem posed must contain the following topics, without limiting itself to this list:

1. Conservation of Mechanical Energy

2. Conservation of the linear or two-dimensional moment.

3. Conservation of the angular Moment.

Pose One real life problem situation that have all three Conservations.

Answer 1

(1) Conservation of Mechanical energy -

Suppose two cars of mass M1 and M2 are travelling on a simple path, speed of M1 is greater than that of M2.

Then both the cars collide each other. Here let us assume that the collision is perfectly elastic means there is no energy loss due to friction or heat. In this case the total kinetic energy before the collision shall be equal to the kinetic energy after the collision.

The related problem is -

A railroad car of mass 2.50x10^4 kg is moving with a speed of 4.00 m/s. it collides and couples with three other coupled railroad cars, each of the same mass as the single car and moving in the same direction with an initial speed of 2.00 m/s. Suppose the collision is perfectly elastic than find the speed of the four cars after the collision?

(2) Suppose two cars having mass 2000 kg and 3000 kg are running with velocities 50 m/s and 40 m/s respectively. Then the two cars collide each other and stick togather as a single object. Then find out the velocity of this combined car using conservation of linear momentum.

(3) Suppose a car of mass 1500 kg is moving around a circle of radius 500 m. The man driving the car has a mass of 70 kg and the other man sitting in the car has a mass of 60 kg. During the driving, the other person (60 kg) jumps off the car. Then find out the new velocity of the car around the circle.