A body of mass 2 kg makes an elastic collision with another body at rest and continues to move in the original direction but with one - fourth its original speed . What is the mass of the body it collides with ?

Options

A. 1.0Kg
B. 1.5 kg
C. 1.8 kg
D. 1.2 kg

Answer

d

Explanation

For head on elastic collision we have
`V_(1)= ((m_(1)-m_(2))u_(1))/(m_(1)+m_(2))+ (2m_(1)m_(2))/(m_(1)+m_(2))`
Here `m_(1) = 2kg, u_(1) = x, u_(2) = 0, v_(1) = x//4`
`:. (x)/(4)= ((2-m_(2))x)/(2+m_(2))implies m_(2)= 1.2kg`