Question

Tom drops a coin from the top of a building. Tom is 90 meters from the ground when he drops the coin.

A) What is the height of the coin exactly 3 seconds after he releases the coin?

B) When the coin hits the ground, how much time has passed from when it was dropped until impact with the ground?

Answer 1

A: 45.9 meters

B: 4.29 seconds

Explanation:

A: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

B: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

In the second question, the numbers aren't exact, but they're a close approximation.