Question

Two ball A and B are moving towards each other. Ball A has a mass of 2kg and is moving with a velocity 5m/s and Ball B has a mass of 3kg and is moving with a velocity 6m/s. Find the final velocity

Answer 1

Use law of conservation of linear momentum,

Let Ua and Ub initial velocity respectively.

Let Va and Vb final velocity respectively.

Ma×Ua+Mb×Ub=Ma×Va+MbVb

2×5+3×6=2×Va+3×Vb

2Va+3Vb=28 ..... (1)

And now use co-efficient of restitution (e) to find velocity,

Let us assume that the collision is perfectly elastic, i.e. e=1.

By formula,

Vb-Va= -1

Va=Vb+1 ..... (2)

Solving 1 and 2,

Vb=26/5

=5.2 m/s

Va=6.2 m/s