Two stones, P and Q, are thrown horizontally from the edge of a cliff into a soft sand bed at the foot. Stone P has a mass of 0.50kg and is thrown with a speed of 10ms−1, while stone Q has a mass of 0.25kg and is thrown with a speed of 20ms−1.
a. (a) Calculate the kinetic energy of each stone just before it strikes the sand.
b. (b) Find the ratio of the kinetic energies of Q to P.
c. (c) The sand exerts the same constant retarding force on each stone. Assuming each stone comes to rest after penetrating the sand, determine the ratio of the penetration depths of Q to P. State which stone penetrates deeper and give a reason based on your calculation.