A rock is thrown vertically upward with a speed of 11.0 m/s from the roof of a building that is 70.0m above the ground. Assume free fall.
a) In how many seconds after being thrown does the rock strike the ground?
b) What is the speed of the rock just before it strikes the ground?

Question

A rock is thrown vertically upward with a speed of 11.0 m/s from the roof of a building that is 70.0m above the ground. Assume free fall.
a) In how many seconds after being thrown does the rock strike the ground?
b) What is the speed of the rock just before it strikes the ground?

anonymous · Answer

take u=11 s=-70 g=-10 and solve for t using s=ut-.5att
for second use v^2=u^+2*a*S

anonymous · Answer

thank u!!