A 3kg ball moving at 8 m/s strikes a 2kg ball at rest, if the collision is elastic, what is the speed of the lighter ball if the heavier ball moves at 2m/s in the opposite direction

Speed of lighter ball is 4 m/s.

Explanation:

Applying the principle of conservation of linear momentum,

momentum before collision = momentum after collision.

+ = -

= 3 kg, = 8 m/s, = 2 kg, = 0 m/s ( since it is at rest), = 2 m/s, = ?

(3 x 8) + (2 x 0) = (8 x 2) - (2 x )

24 + 0 = 16 - 2

2 = 16 - 24

2 = -8

=

   = -4 m/s

This implies that the light ball moves at the speed of 4 m/s in the opposite direction of the heavier ball after collision.

gravity

explanation:

their crystal patterns have been disrupted by stress