A ball is launched straight up at 39.2 m/s. Air resistance is ignored. Taking up as positive, what is its velocity 3 s after launch? Enter the value in m/s, including its sign.
Toss a set of keys straight up and watch closely. At the very top of the flight they seem, for a flash, to hang in the air. What is actually true at that instant?
Two quantities describe that instant, and they behave very differently.
At the top of the flight the velocity is zero for an instant: the keys have stopped rising and have not yet started falling.
The acceleration does not share that pause. It remains 9.8 m/s² downward at the top — the same value as during the rise and during the fall.
Try it on a fresh case. A juggling ball reaches the top of its flight. Its velocity is zero, for an instant. Its acceleration is 9.8 m/s² downward, unchanged.
A coin flipped straight up is at the highest point of its flight. What is its velocity at that instant?
A basketball is at the highest point of its flight. What is the magnitude of its acceleration at that instant? Enter the value in m/s².
An arrow shot straight up is at the highest point of its flight. Which pair of statements about that instant is correct?
A volleyball is tapped straight up. For how long is its velocity zero at the top of its flight?
An apple is tossed straight up. Which statement about the apple at the very top of its toss is correct?
A ball thrown straight up passes point P partway up and reaches its highest point at Q. At which point, if either, is the magnitude of its acceleration smaller?