Question

A 6.00kg mass is traveling with a velocity of 2.00m/s to the east, and an 8.00kg mass is traveling with a velocity of 5.00m/s to the west as shown in the figure. The two masses collide, and after the collision the 8.00kg mass has a velocity of 3.60m/s directed at an angle of 34° west of north. a) What is the velocity of the 6.00kg mass after the collision? b) Was the collision elastic? Show enough work to justify your answer.

Answer 1

Solution:

Given,

, , , ,

(a) Let the velocity of after collision be and it moves at an angle west of south.

By the principle of conservation of momentum,

Total momentum before collision= Total momentum after collision.

In horizontal direction, we have;

  

  

.............. (1)

In vertical direction, we have;

  

................. (2)

Eq. (1) divided by Eq. (2), we get

  

  

Thus,

The velocity of 6.00kg after collision is .

(b) Total kinetic energy before collision is

  

  

Total kinetic energy after collision is

  

  

From both we have,

Thus the collision is not elastic.