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1. About 140 million years ago, South America and Africa were joined together. Now,
because of continental drift, they are about 4000 km apart. Calculate the average
speed of separation in millimeters per year. (4 marks)
2.
For the graph shown, find the average velocity between
a) 20 to 24 s (2 marks)
b) 14 to 18 s (2 marks)
3.
For the graph shown, if the curve is for uniformly accelerated motion, what is the
instantaneous velocity at 15 s? (3 marks)
4. The following is a velocity-time graph of a car’s motion. Draw a position-time graph
and an acceleration-time graph for the car. (5 marks)
5. For the graph in question 4, if the car started with zero displacement,
a) what is its displacement after 40s? (1 mark)
b) what is its change in displacement between 25 and 40 s? (2 marks
6. A rock is thrown vertically upwards with a velocity of 20 m/s from the edge of a bridge
42 m above a river. How long does the rock stay in the air if it lands in the river?
(3 marks)
7. A platform diver jumps vertically upwards with a velocity of 4.2 m/s. The diver enters
the water 2.5 s later. How high is the platform above the water? (3 marks)
8. Police find skid marks 60 m long on a highway showing where a car made an
emergency stop. Assuming that the acceleration was -10 m/s2 (about the maximum for
dry pavement),
a) how fast was the car going? (2 marks)
b) how much did the car exceed the 80 km/h speed limit? (1 mark)
c) how long did it take to stop? (2 marks)
9. A jet plane traveling at +88 m/s lands on a runway and comes to rest in 11 s.
a) Calculate its uniform acceleration. (2 marks)
b) Calculate the displacement it travels. (2 marks)
10. An accelerating lab cart passes by point A and then point B which are 3.0 m apart in
4.2 s. The velocity of the cart at the second point is 1.2 m/s [S]. What is the
acceleration? (3 marks)
11. Stations A and B are 3 km apart on a straight rail track. A train from A heads towards
station B at a steady velocity of 25 m/s [E]. At exactly the same time, another train
passes B and approaches station A at a fixed velocity of 35 m/s [W] on the other line.
How far are the trains from station A when they pass each other? (2 marks)
12. Two balls are released at the same time from a building from two points in the same
vertical plane. Ball A is thrown vertically down from point A with a velocity of
-50 m/s. Ball B is dropped from a window ledge 30 m below. How long will it take
before the balls meet? What is ball A’s displacement in this time? (2 marks)
13. For the graph below, positive is up and negative is down.
a) What is the object’s displacement after 35 s? Remember to answer up or down
(1 mark)
b) What is the object’s direction of acceleration between 10 and 15 s. (1 mark)
c) What is the direction of displacement (up or down) between 35 and 40 s?
(1 mark)
d) When is the object’s velocity downwards while its acceleration is
upwards and the displacement is increasing downwards? Note that all
three conditions must exist at the time(s). (2 marks)
November 18, 2013
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