A body of mass 5 kg makes an elastic collision with another body at rest and continues to move in the original direction after collision with velocity equal to `(1)/(10)`th of its original velocity . Then the mass of the second body is

Options

A. 4.09kg
B. 0.5kg
C. 5kg
D. 5.09kg

Answer

a

Explanation

Velocity of the body after first collision
`v_(1)=[(m1-m2)/(m1+m2)]mu1`
thererfore`mu1/10=[(m1-m2)/(m1+m2)]mu1[therefore ,v1=mu1/10]`
`5+m_(2)=(5-m_(2))xx10`
`5+m_(2)=50-10m_(2)`
`m_(2)=45/11` =4.0kg`