A ball is dropped at time t = 0.0 s. At t = 2.0 s, a second ball is thrown downward with speed v. What is v if at t = 4.0 s, the two balls are at the same vertical position?
A) 15 m/s
B) 25 m/s
C) 49 m/s
D) 29 m/s

Question

Quizplus · Accepted Answer

The first ball falls freely under gravity for 4 seconds, covering a distance of 0.5 * 9.8 * (4^2) = 78.4 m. The second ball is thrown at t = 2 s and falls for 2 seconds. To cover the same distance, 78.4 m, in 2 seconds, its initial speed v must satisfy the equation: 78.4 = v * 2 + 0.5 * 9.8 * (2^2). Solving for v gives v = 29 m/s.

A Ball Is Dropped at Time T = 0