Physics 20
Unit A: Kinematics
Practice Problems
Kinematics Review Problems
1. A volcano shoots out blobs of lava called lava bombs. A geophysicist observes that the bombs travel straight up. If the time in the air is 4.75 s, determine the initial speed of the lava bombs.
2. The golfer in the diagram below sinks the ball in two putts. What is the magnitude and direction of the ball's displacement?
3. In a well-known Jules Verne novel, Phileas Fogg travels around the world in 80 days. If the radius of the Earth is 6.37 x 10
6m, what is his average speed in m/s?
(Hint: find the distance around the Earth!)
4. The sport with the fastest ball speed is jai alai, where speeds of 303 km/h have
been measured. If a player faces a ball moving at that speed and blinks, his eyes
are closed for 100 milliseconds. How far does the ball move during that time?
5. A child slides down a hill on her sled. The hill is 54.9 m long. If the child starts from rest, and reaches the bottom in 9.65 s, determine her acceleration.
6. What is the speed of the child in question 5 at the bottom of the hill?
7. A bullet leaves the barrel of a gun at 400 m/s. If the barrel is 0.500 m long, how long is the bullet in the barrel after the trigger is pulled?
8. A person on a trampoline bounces straight up at 4.5 m/s. What is the person's
speed when she reaches the trampoline again?
9. A hot air balloon is going down at 2.0 m/s when a tourist drops her camera. If the balloon was 45 m above the ground, at what speed will the camera hit the dirt?
10.Superman is flying when he sees some evil scoundrel stealing candy from a baby. He reaches the scoundrel at 87.2 m/s in a time of 3.00 s. If his acceleration was 5.91 m/s
2, how far did he travel in this time?
Answers
1. 23.3 m/s 2. 10 m right 3. 5.8 m/s 4. 8.42 m 5. 1.18 m/s2 6. 11.4 m/s 7. 2.50 x 10-3 s 8. 4.5 m/s 9. 30 m/s 10. 235 m
Kinematics Review
Use the following velocity vs. time graph for an object moving west to answer the next three questions.
1. When is the object moving at uniform speed?
a. W b. X c. Y d. Z e. W and Z
2. When is the acceleration of the object the largest magnitude?
a. W b. X c. Y d. Z
e. W and Y have the same acceleration.
3. When is the object moving east?
a. W b. X c. Y d. Z e. X and Y
The letters in circles each
represent a portion of the object’s motion.
W
Use the following displacement vs. time graph for an object moving west to answer the next two questions.
4. The average velocity of the object in the interval 2.0 s to 8.0 s is _______.
5. The total distance travelled by the object is ______.
6. Volcanoes on Io (a moon of Jupiter) eject rocks vertically to heights of 2.00 x 105 m. The acceleration of gravity on Io is 1.80 m/s2. Determine the initial velocity of the rocks.
7. Calvin begins moving down his favourite toboggan hill with an initial velocity of 2.00 m/s.
After 4.80 s, he has moved a distance of 16.7 m. Determine his acceleration during this time.
8. An airplane sets a course of 22o E of N at an airspeed of 800 km/h. A wind is blowing at 70 km/h east. Determine the resulting velocity.
9. A rock is thrown horizontally at 7.0 m/s from the top of a 25 m high cliff. How high from the base of the cliff is it 1.2 s later? What is its velocity magnitude at this time?
10. Danielle is skateboarding down the sidewalk at 10.0 m/s east. Then she turns around and is moving at 12.0 m/s west. Calculate her displacement after 15.0 s.
11. At 3:21 pm on the last day of class, Mr. Boyd throws his calculator straight up at 10.0 m/s in the parking lot. How high above the ground is the calculator 1.55 s after it leaves his hand?
12.A 0.25 kg ball strikes the floor at 5.7 m s and rebounds with the same speed and angle to the floor as shown. The ball’s contact time was 0.22 s. Calculate the magnitude of the ball’s acceleration.
13. A cannonball is fired on Earth at an angle of 45o above the ground and has a range of 125 m. If the same cannonball is fired on Jupiter where g = 24.6 m/s2, which combination of changes would have to occur so that the cannonball still has a range of 125 m?
14. A new gunner in the Calgary artillery is accidentally fired out of a cannon at 110 m/s at 55.00 to the horizontal. How far away will he land?
Projectile Problems
1. Mr. Wong throws his calculator into the air at an angle of 20.0o at 10.0 m/s. How high does it go?
2. James Bomb (the unluckiest secret agent) drives his car off a horizontal mountain road that is 46.2 m above the valley floor. He lands in a snow bank 98.2 m from the base of the cliff. How fast was James driving
?
3. A student standing on a knoll (a small hill) throws a snowball horizontally 4.5 m above the level ground towards a smokestack 15 m away. The snowball hits the target 0.65 s later. How high above the level ground does the snowball hit the smokestack?
4. A machine launches tennis balls at an angle of 45o to the horizontal with an initial vertical velocity of 9.0 m/s and a horizontal velocity of 9.0 m/s. The balls reach their maximum height above ground 0.92 s after launch. Find the maximum horizontal distance traveled by the balls. Assume the balls land at the same height above ground as they are launched.
5. A hammer slides off a 15 m high roof at 4.6 m/s as shown below. How much time does it take for the hammer to hit the ground?
6. Jack Splat is planning a daring escape from prison. He plans to be launched from a cannon at 45.0 m/s at an angle of 45.0o. The end of the barrel is 2.00 m above the ground. A 12.0 m high brick wall is located 15.0 m from the cannon. Will Jack make it over the wall?
7. Fluffy the bunny hits a golf ball at 18.5 m/s at an angle of 50.0o. How far away does it land?
