Question

A lump of clay (m₁ = 0.2 kg) moving horizontally with a speed v_o1 = 16 m/s strikes and sticks to a wood block (m₂ = 3 kg) which is initially at rest on the edge of a horizontal table of height h = 1.5 m. Neglecting friction, find 

(a) the horizontal distance x from the edge of the table at which the clay and block strike the floor, and 

(b) the total momentum of the clay and block just before they strike the floor.

Answer 1

The sketches below represent the system before, during, and after the collision.

(a) Before we can find the horizontal distance the clay and block travel we need to find their speed vf as they leave the edge of the table. Momentum is conserved in this inelastic collision:

Then the horizontal distance traveledis

(b) The momentum of the clay and block just before it strikes the ground can be found by finding the horizontal and vertical components of the momentum: