Q. Plastic collosion of two bodies of equal mass results in a common velocity after impact which is

• (A) Sum of their initial velocities
• (B) In lowering a weight of 100 kg along an a inclined plane at an angle of 45? with
• (C) In lifting up a weight of 100 kg at a constant speed of 3 m/sec
• (D) In lowering the weight at a constant speed of 3 m/sec