Kinematics In-Class Practice Problems (This is not homework!)

 

1.      A person moves on the number line shown below.  The person begins at point B, walks to
pt. C, and then turns around and walks to pt. A.  For this entire range of motion determine: (a) the person’s final position, (b) the displacement, and (c) the distance.

 


2.      An ant crawls clockwise along the perimeter of the circle from A to B.  The circle has radius 5.00 cm and C is its center.  Use the center of the circle as your point of reference as you determine: 
(a) the ant’s initial position,
(b) the ant’s final position,
(c) the ant’s displacement, and
(d) the ant’s distance.


3.      Using the given information try to determine the motion of a person along a number line where point A is at the origin.  Note: there may be multiple solutions, one solution, or no solution.
(a) sf = 2 m, 0° from A; d = 3 m, 0°; d = 3 m
(b) si = 0 m from A; d = 0 m; d = 4 m
(c) sf = 1 m, 180° from A; d = 2 m, 180°; d = 6 m
(d) si = 3 m, 0° from A; d = 2 m, 0°; d = 0 m

4.      An avid shopper has an average speed of 0.22 m/s while shopping in the mall for 3.0 hours.  During this time her displacement is 100 m, 180.0°.  Find the distance she traveled and her average velocity.

5.      Sound travels with constant speed of 343 m/s in typical conditions.  (a) Find the distance sound travels in 1.00 minute.  (b) Determine the time for sound to travel 100 m.

6.      Suppose lightning occurs 1.00 mile away (about 1609 m).  How much time elapses between seeing the lightning and hearing the thunder it causes?  The speed of light is constant through air:  3.00 ´ 108 m/s.

7.      A commuter drives 15.0 km on the highway at a speed of 25.0 m/s (56 mph), parks at work and walks 150 m at a speed of 1.50 m/s from his car to his office.  (a) Determine the total time of the commute.  (b) Determine the average speed of the entire commute.  Repeat for highway speeds of 30.0 m/s (67 mph) and 35.0 m/s (78 mph).

8.      The weather at Milliville, tracking a thunderstorm’s position, records the following values: 
4:00 pm      5.50 miles, 284.5° from Milliville
4:30 pm      1.25 miles, 225.0° from Milliville
5:00 pm      4.78 miles, 131.5° from Milliville
Chart the storm’s course with ruler and protractor and determine the thunderstorm’s speed and direction.  Can it be determined if the speed and direction are constant?

9.      Mr. M’s car goes from 0 to 60 mph in 15 s, traveling east.  Find its acceleration.

10.  Still traveling east, Mr. M steps on the brakes – decreasing his speed from 60 mph to 20 mph in 2.5 s.  Find his acceleration.

11.  Starting from rest, a sprinter attains a velocity of 12 m/s, 180° in 3.2 s.  Find the sprinter’s acceleration.

12.  A falling acorn gains speed from 5.00 m/s to 19.7 m/s in 1.50 seconds time.  Find its acceleration.

13.  A police car skids to a stop in 3.90 s.  Just before hitting the brakes the velocity was 35.0 m/s, 180.0°.  Find the acceleration.

14.  A bungee jumper has velocity 21 m/s, 270° just as the bungee cord begins to stretch.  The bungee cord slows the person to a stop and shoots them back upward.  The person’s velocity is 14 m/s, 90° at a time 2.5 seconds after the bungee cord first began to stretch.  Determine the acceleration caused by the bungee cord.

15.  Starting from rest a powerful car accelerates 4.00 m/s2, 0.0° for 6.00 s. (a) Find the car’s final velocity.  (b) Find the car’s displacement during this same interval.

16.  The same powerful car passes Mr. M. in his VW bus, going from 24.0 m/s to 29.0 m/s in 2.00s during the process.  (a) Find the acceleration rate of the car.  (b) Find the distance the car travels as it passes the bus.

17.  The maximum deceleration rate for most cars is about 9.0 m/s2.  For a car traveling 25 m/s, calculate the minimum stopping distance and time.  Repeat for a car traveling 50 m/s initially.

18.  A sport’s car (Dodge Viper) claims to go from 0 to 100 mph (45 m/s) and back to 0 in 14.7 s.  If 4.7 s of this time is spent in braking the car, what is the total distance covered?

19.  A steam driven catapult accelerates a 20 ton aircraft from 0 to 66 m/s in 3.0 s to launch the plane from the deck of an aircraft carrier.  (a) Find the rate of acceleration.  (b) Determine the length needed for the runway on the deck of the carrier.

20.  An eleven pound projectile leaves the barrel of an experimental “super gun” with speed 9000 mph.  The barrel is 155 feet long.  Determine the acceleration rate, assuming it to be uniform.

21.  You are designing an interstate exit ramp.  The ramp must give adequate space for cars to slow to a stop.  Maximum “comfortable” deceleration is 4.0 m/s2.  The speed limit is 29 m/s.  How long should the ramp be at minimum?

22.  You enter the interstate on a ramp that is 0.10 km long.  If you wish to attain the speed limit of 29 m/s before merging, what must be your acceleration rate?  Is this a well designed ramp?

23.  A reckless driver hits a 110 m exit ramp doing 45.0 m/s.  If his acceleration due to braking is 8.00 m/s2, find:  (a) time to get to the end of the ramp, and (b) speed at the end of the ramp.

24.  A bungee jumper has velocity of 20.0 m/s, 270.0° just as the cord begins to stretch.  The bungee causes an acceleration of 15.0 m/s2, 90.0°.  (a) Find the time the jumper is pulled by the cord.  (b) Find the amount the cord is stretched beyond its original length.

25.  Cats have been known to survive long falls out of apartment windows in NY city.  Assuming 12 floors is 40 m high, estimate a cat’s impact speed after falling this distance.

26.  A baseball is “popped up” with initial velocity 20.0 m/s, 90.0°.  Find the maximum height to which the ball will rise.  Find the total time the ball takes to return to its initial position.

27.  A bungee jumper uses a bungee cord with an unstretched length of 25 m.  The jumper freefalls this amount and then the cord stretches to a length of 55 m.  (a) Estimate the maximum speed attained by the person.  (b) Find the average acceleration which results from the stretching cord.

28.  A ball thrown with what initial upward speed would rise to a height of 10.0 m?

29.  A football player spikes the ball by throwing it downward at 10.0 m/s from a height of 1.00 m.  Determine the impact speed of the ball.