Collisions Introduction

If momentum and kinetic energy transfers from one body to another during interaction of one body with other is called collision. Any way physical interaction of one body with other is not important and collsion is said to be happened when there is transfer of momentum and kinetic energy.

For example during Rutherford Gold foil experiment some of alfa particles are said to be collided with nucleus when they got deviated from their original path even when they have no physical interaction and it happens because of their repulsive forces.

If both momentum and kinetic energy are conserved during a collision it is said to be elastic and if only momentum is conserved it is said to be inelastic. In the inelastic collision the loss of some of energy happens in the form of sound, heat and light.

The total kinetic energy of the system is not necessarily conserved. The impact and deformation during collision may generate heat and sound. Part of the initial kinetic energy is transformed into other forms of energy.

A useful way to visualise the deformation during collision is in terms of a ‘compressed spring’. If the ‘spring’ connecting the two masses regains its original shape without loss in energy, then the initial kinetic energy is equal to the final kinetic energy but the kinetic energy during the collision time Δt is not constant. Such a collision is called an elastic collision.

The deformation may not be relieved and the two bodies could move together after the collision. A collision in which the two particles move together after the collision is called a completely inelastic collision.

The intermediate case where the deformation is partly relieved and some of the initial kinetic energy is lost is more common and is appropriately called an inelastic collision.

Consider two masses m1 and m2. The particle m1 is moving with speed v1i , the subscript ‘i’ implying initial. We can cosider m2 to be at rest. No loss of generality is involved in making such a selection. In this situation the mass m1 collides with the stationary mass m2 and this is depicted in Fig.

The masses m1 and m2 fly-off in different directions. We shall see that there are relationships, which connect the masses, the velocities and the angles.

Related posts :

Potential Energy of a spring
Motion of a body in vertical circle
Work
work done by variable force


No comments:

Post a Comment