# Physics:A ball is attached to one end of a wire, the other end being fastened to the ceiling. The wire is held [Solved]

Conserve momentum: initial p = final p
1.6kg * 5.2m/s = 1.6kg * u 2.47kg * v substitute for v from above
8.38 = 1.6u 2.47(5.2 u) = 12.9 4.07u
-4.62 = 4.07u
u = -1.1 m/s (Ill call this negative) ball
v = 5.2 u = 4.1 m/s (positive) block

(a) Use conservation of energy to get the pre-impact velocity:
v = (2gh) = (2 * 9.8m/s * 1.4m) = 5.2 m/s
See drawing for direction. Ill call it positive.

(b) Since we have an elastic head-on collision, we know (from CoE) that
the relative velocity of approach = relative velocity of separation, or
5.2 m/s = v u
v = 5.2 u
where v, u are the post-collision velocities of the block, ball respectively

Conserve momentum: initial p = final p
1.6kg * 5.2m/s = 1.6kg * u 2.47kg * v substitute for v from above
8.38 = 1.6u 2.47(5.2 u) = 12.9 4.07u
-4.62 = 4.07u
u = -1.1 m/s (Ill call this negative) ball
v = 5.2 u = 4.1 m/s (positive) block

This post is last updated on hrtanswers.com at Date : 1st of September – 2022