You throw a ball straight up into the air. Describe the acceleration of the ball at the moment it reaches maximum height?

a roller coaster begins its movement from an initial height of 25 m in the air and an initial velocity of 0 m/s. Later in the movement, the roller coaster is moving at 12 m/s. Calculate the height of the roller coaster at this point, assuming the roller coaster and track are an isolated system.

Your little sister is running to the park in your neighborhood at a speed of 3.90 m/s when you suddenly realize she left her favorite playground ball behind. You throw her ball horizontally out the window of your apartment which is at a height of 45.0 m above the street and directly above the sidewalk. You throw the ball 8.00 seconds after she has passed below your window and she catches the ball! a) Ignoring air resistance, what is the initial speed that you must throw her ball so she can catch it just before it reaches the ground? b) How far down the sidewalk from the window is your sister when she catches her ball?

7. You are sitting in a helicopter that is climbing directly upward at a constant velocity of 2.5 m/s. The helicopter door is open, and you notice that a small screw slips out the door. You can assume the screw has no horizontal component to its velocity. (a) What is the velocity of the screw 4.0 s after falling out of the helicopter? (b) How far below the helicopter is the screw at this time?

You are diving board over a swimming pool. You are throwing upward a tennis ball at a speed 3 m/s. On its way back down the tennis ball narrowly misses the diving and hits the water below at 15 m/s. The board is about

A rock is thrown straight downward near the Earth’s surface with initial velocity of 20m/s down.  Assuming it doesn’t reach the ground, after 4 seconds its speed will be about

15) You are standing on a cliff 50 m high and throw a rock with an initial velocity of 20 m/s straight up so that the rock eventually lands at the base of the cliff (50 m below you). How long is the rock in the air? a) What is the maximum height of the rock? b) What is the final velocity of the rock? c)

A crossbow bolt is fired horizontally over level ground toward a target 37.4 m away. The bolt hits the target 0.24 m below the height at which it was fired.what was the initial speed of the bolt in m/s?