At time t = 0, a student throws a set of keys vertically upward to her sorority sister, who is in a window at distance h above. The second student catches the keys at time t.

(a) With what initial velocity were the keys thrown? (Use any variable or symbol stated above along with the following as necessary: g.)

(b) What was the velocity of the keys just before they were caught? (Use any variable or symbol stated above along with the following as necessary: g.)

Question

At time t = 0, a student throws a set of keys vertically upward to her sorority sister, who is in a window at distance h above. The second student catches the keys at time t. 

(a) With what initial velocity were the keys thrown? (Use any variable or symbol stated above along with the following as necessary: g.)

(b) What was the velocity of the keys just before they were caught? (Use any variable or symbol stated above along with the following as necessary: g.)

anonymous · Answer

We do not know the velocity when the keys were caught, though perhaps it was 0.

h= u t - (1/2) g t^2 for height versus time

v = u - g t                for  velocity if started at u velocity