Question 131: Centre of Mass and Rotational Motion

Question

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.Assertion A : Body 'P' having mass M moving with speed 'u' has head-on collision elastically with another body 'Q' having mass 'm' initially at rest. If m << M, body 'Q' will have a maximum speed equal to '2u' after collision.Reason R : During elastic collision, the momentum and kinetic energy are both conserved.In the light of the above statements, choose the most appropriate answer from the options given below :

Accepted Answer

m < < M
e = $${{{v_2} - {v_1}} \over {{u_1} - {u_2}}}$$
For elastic collision $$ 	o $$ e = 1
1 = $${{{v_2} - u} \over {u - 0}}$$
u = v
2
$$-$$ u
v
2
= 2u
In elastic collision kinetic energy & momentum are conserved.

Answer

A is correct but R is not correct.

Answer

A is not correct but R is correct.

Answer

Both A and R are correct and R is the correct explanation of A.

Answer

Both A and R are correct but R is NOT the correct explanation of A.

Centre of Mass and Rotational Motion

Choose the correct answer: