Question

If the two particles strike the rod in opposite direction, then after collision, as compared to the previous situation the rod will

• A. rotate faster but translate at the same rate
• B. show no change in linear or angular velocity
• C. rotate slower and translate faster
• D. rotate faster and translate slower

Answer 1

The correct option is D rotate faster and translate slower

When both the particles will strike the rod in the opposite directions then their momentum will be in opposite direction so for getting the net momentum they will get subtracted from each other. So the momentum imparted to the rod will be less as compared to this present case when particles are on the same side where momentum will be added and more momentum will be imparted to the rod.

So in the second case translation speed will be slower.

Also In the first case, the torque with respect to the centre of the impulse due to these particles are on the opposite direction, so for net torque, this torque will be subtracted from each other and net torque imparted to the rod will be less.

While in the second case when the particles are in the opposite direction torque will be in the same direction and will add up to give the net torque imparted to the rod. Hence, as in the second case torque will be more so the angular velocity of the rod will be higher so the rod will rotate faster.