An object has increasing velocity when its acceleration is greater than zero. It has increasing speed when its velocity and acceleration have the same sign. For what times is: a. the velocity of the ball increasing? b. The speed of the ball increasing?

1. A stone is dropped from the top of a cliff. It is seen to hit the ground below after 4.5 seconds. How high is the cliff? 2. A ball is thrown vertically downward with a velocity of 20 m/s from the roof of a building that is 25 m high. How long does it take to hit the ground below? b. How fast was the ball going when it hit the ground? 3. A coin is tossed vertically upward and reaches a maximum height of 1.5 meters before it comes back down. What was its initial velocity? b. How long was it in the air? a. 4. A car rolls gently off a vertical cliff with an initial velocity of 0 m/s. How long does it take for the car to reach a speed of 75 km/hr? 5. The best rebounders in basketball have a vertical leap of about 125 cm. a. What is their initial launch speed off of the ground? b. How long are they in the air? 6. King Kong climbed the Bank of America Plaza in Atlanta which has a height of 312 m. a. How long did it take for him to fall? b. What was his velocity just before hitting the…

A space probe leaves the solar system to explore interstellar space. Once it is far from any stars, when must it fire its rocket engines? A. only when it wants to slow down B. when it wants to speed up C. all the time, in order to keep moving 19 D. only when it wants to turn E. only when it wants to speed up

Before the SpaceX Falcon 9 rocket enters into outer space, it accelerates upward according to a(t)=3t^2 in the unit of m/s^2. Find the speed of the rocket at t = 5.0s? Assume the initial speed of the is 10 m/s. rocket O A. 125 m/s O B. 75 m/s O C. 135 m/s O D. 10 m/s