Question

A steel ball of mass 200g moving with a velocity of 10 m/s collides elastically with another ball of same mass at rest, then calculate the followings. (your answer must be in SI units) (4 points)
a. Total momentum of the system before collision =
b. Total Kinetic energy of the system before collision =
c. Total momentum of the system after collision =
d. Total Kinetic energy of the system after collision

Answer 1

Elastic collision is that type of collision in which both momentum and kinetic energy remain conserved before and after collision . So we can say that total kinetic energy before collision must be equal to total kinetic energy after collision.

a) total momentum before collision is given by

p = m(v1 + v2)

Here 2nd ball is at rest so v2 = 0 m/a

p = 0.2kg × 10 m/s = 2 kgm/s

b) total kinetic energy of the system before collision is given by

K.E = 0.5 m ( v1² + v2²)

K.E = 0.5 × 0.2 ( (10)² + 0²)

K.E = 10 J

c) tatal momentum after collision is same as before collision

p = 2 kgm/a

d) total K.E is also same

K.E = 10J