A ball A is dropped from rest from the top of an high tower

PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

A ball A is dropped from rest from the top of an

80\,\text{m}

high tower. One second later, another ball B is projected vertically upward from the ground with a speed of

25\,\text{m}\,\text{s}^{-1}

. (Take

g = 10\,\text{m}\,\text{s}^{-2}

downward.) At what height above the ground will the two balls pass each other? (a)

57\,\text{m}

(b)

28.8\,\text{m}

(c)

31\,\text{m}

(d)

48.8\,\text{m}