Acceleration

19) A sports car moving at constant speed travels 110 m in 5.0 s. If it then brakes and comes to a stop in 4.0 s, what is its acceleration in m/s²? Express the answer in terms of "g's", where 1.00 g = 9.80 m/s².

Motion at Constant Acceleration

21) A car accelerates from 13 m/s to 25 m/s in 6.0 s. What was its acceleration? How far did it travel in this time? Assume constant acceleration.

23) A light plane must reach a speed of 33 m/s for takeoff. How long a runway is needed if the (constant) acceleration is 3.0 m/s²?

25) A car slows down uniformly from a speed of 21.0 m/s to rest in 6.00 s. How far did it travel in that time?

Falling Objects [neglect air resistance]

33) A stone is dropped from the top of a cliff. It hits the ground below after 3.25 s. How high is the cliff?

39) A helicopter is ascending vertically with a speed of 5.20 m/s. At a height of 125 m above the Earth, a package is dropped from a window. How much time does it take for the package to reach the ground? [Hint: The package's initial speed equals the helicopter's]

45) A rock is dropped from a sea cliff, and the sound of it striking the ocean is heard 3.2s later. If the speed of sound is 340 m/s, how high is the cliff?

47) A stone is thrown vertically upward with a speed of 12.0 m/s from the edge of a cliff 70.0 m high.

a) How much later does it reach the bottom of the cliff?

b) What is its speed just before hitting?

c) What total distance did it travel?