JEE MAIN - Physics (2021 - 26th February Morning Shift - No. 16)
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 :
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 :
A is correct but R is not correct.
A is not correct but R is correct.
Both A and R are correct and R is the correct explanation of A.
Both A and R are correct but R is NOT the correct explanation of A.
Explanation
_26th_February_Morning_Shift_en_16_1.png)
m < < M
e = $${{{v_2} - {v_1}} \over {{u_1} - {u_2}}}$$
For elastic collision $$ \to $$ e = 1
1 = $${{{v_2} - u} \over {u - 0}}$$
u = v2 $$-$$ u
v2 = 2u
In elastic collision kinetic energy & momentum are conserved.
Comments (0)
