Question

Two particles collide and stick together. If no external forces act on the two particles, which of the following is correct for the change in total momentum Δp and the change in total kinetic energy ΔK of the two particles?
a. p<0, K<0.
b. p<0, K=0.
c. p=0, K<0.
d. p=0, K=0.
e. p=0, K>0.

Answer 1

Answer:

c.$\Delta p$=0 and $\Delta k$

Explanation:

We are given that two particles collide  and stick together.

If there is no external force act on the two particles then ,it is inelastic collision.

Inelastic collision: There is some loss of kinetic energy but the momentum is conserved.

According to law of conservation of momentum

Initial momentum=Final momentum

Change in momentum=Final momentum-Initial momentum=0

Change in momentum=$\Delta p=0$

Initial kinetic energy is greater than final kinetic energy.

Change in kinetic energy=Final kinetic energy-kinetic energy=- negative

$\Delta k$

Hence, option c is true.

c.$\Delta p$=0 and $\Delta k$