A rock is tossed straight up from ground level with a speed of 22 m/s. When it returns, it falls into a hole 9.0 m deep. a. What is the rock’s velocity as it hits the bottom of the hole? b. How long is the rock in the air, from the instant it is released until it hits the bottom of the hole?

(a)

(b)

Explanation:

We will take ground level as origin and upward is positive direction

the givens are

Part (a)

To find the final velocity we use the kinematic equation

So

Part (b)

To find time of rock trip until it touches the ground we will use simple kinematic equation or simple motion equation

Notice that we substituted vf with negative sign because its direction is downwards

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)