Equate energies:
Initial kinetic energy = (1/2)mu²
Final kinetic energy = (1/2)mv²
Potential energy = mgh = (1/2)m(v²-u²)
Solve for h
A rock thrown straight up with a velocity of
30 m/s from the edge of a building just misses
the building as it comes down. The rock is
moving at 47 m/s when it strikes the ground.
How tall was the building? The accelera-
tion of gravity is 9.8 m/s2 .
Answer in units of m.
1 answer
1 answer