Question 1: An object is thrown straight up into the air from the top of a building at a velocity of 15 m/s. If it hits the ground in 8.0 seconds, what is the height of the building? Ignore air resistance.


Question 2: An object is thrown straight up into the air from the top of a building at a velocity of 12 m/s. If it hits the ground in 8.0 seconds, what is the speed of the object when it hits the ground? Ignore air resistance.

What have you tried so far?

1. Use s = ut + \frac12 at^2

where s is the vertical displacement,
u the initial speed.
t the time taken.
a the acceleration due to gravity.

2. Here, you can use v = u+at

where v is the final velocity of the object when it hits the ground.

Post what you get! :)