Question

Joe Average throws an apple vertically into the air, and then catches it at the same height. The apple is in the air for 2.5s. What is the apple's velocity the moment it's thrown? (choose the correct number of significant figures for your answer) _m/s

Answer 1

Answer:

The apple's velocity when it's thrown is 12.25 m/s

Explanation:

Vertical Launch Upwards

In a vertical launch upwards, an object is launched vertically up without taking into consideration any kind of friction with the air.

If vo is the initial speed and g is the acceleration of gravity, the time it needs to reach the maximum height is:

$\displaystyle t=\frac{v_o}{g}$

Once it reaches the maximum height, the object takes the same time to go back to the launch point.

The apple thrown by Joe Average takes 2.5 s to complete the whole flight, thus the time it went up is t=2.5/2=1.25 seconds.

From the equation above, we solve for vo:

$v_o=gt= 9.8*1.25$

$v_o=12.25\ m/s$

The apple's velocity when it's thrown is 12.25 m/s