KINEMATIC EQUATIONS:
vf = vi +at
d = 1/2(vi + vf)t
d = vit + 1/2 at2
vf2 = vi2 + 2ad
1) A brick is dropped from a scaffold.
(a) What is its velocity after 4.0 s?
(b) How far does the brick fall during this time?
2) A tennis ball is thrown straight up with an initial speed of 22.5 m/s. It is
caught at the same distance above the ground.
(a) How high does the ball rise?
(b) How long does the ball remain in the air?
3) A spaceship far from any star or planet accelerates uniformly from 65.0 m/s to
162.0 m/s in 10.0 s.
(a) How far does it move?
(b) What is its acceleration?
4) Members of a physics class stood 25 m apart and used stopwatches to measure the time a car driving down the highway passed each person. The data they compiled are shown in the following table:
| Time (s) | Displacement (m) |
| 0 | 0.0 |
| 1.3 | 25.0 |
| 2.7 | 50.0 |
| 3.6 | 75.0 |
| 5.1 | 100.0 |
| 5.9 | 125.0 |
| 7.0 | 150.0 |
| 8.6 | 175.0 |
| 10.3 | 200.0 |
(a) Plot a graph of the displacement vs. time for the motion of the car.
(b) What is the car's velocity at t = 7.8 s?
5) A helicopter is rising at 5.0 m/s when a bag is dropped out of the helicopter. After 2.0 s,
(a) what is the bag's velocity?
(b) how far has the bag fallen?
(c) how far below the helicopter is the bag (remember, the helicopter continues to rise at 5.0 m/s)?
6) Races are timed to 1/1000 of a second. What distance could a roller blader moving at a speed of 10 m/s travel in that period of time?
7) A bacterium swims with a speed of 3.5 micrometers/second. How long would it take this bacterium to swim across a petri dish having a diameter of 8.4 cm?
8) A speedboat increases in speed uniformly from 20 m/s to 30 m/s in a distance of 200 m. Find the acceleration and the time it takes to travel this distance.
9) If one object has a greater speed than a second object, does the first necessarily have a greater acceleration? Explain, using examples.
10) A car slows from 25 m/s to rest in 5 s. How far did it travel in that time?
11) A car traveling at 90 km/h strikes a tree. The front end of the car compresses and the driver comes to rest after traveling 0.80 m. What was the average acceleration of the driver during the collision?
12) FOR YOU FORENSIC EXPERTS: In coming to a stop, a car leaves skid marks 80 m long on the highway. Assuming a deceleration of – 7.00 m/s2, estimate the speed of the car just before braking.