Physics
Significant Digits and Scientific Notation
1. What is the number of significant digits in the following numbers? a) 100.0 kg _______ b) 0.0020 _______
2. Calculate the following using correct significant digits. Include the proper units. a) 5.0 g + 10.00 g + 10.000 g ________________
b) 10.0 m 10.0 m 10.00 m _________________
3. Convert the following to the desired units. Answer to proper sig digs. a) 7700 cm/min to m/s b) 11.8 m/s to km/h
4. A person walks 50 m South, then walks 80 m North, and finally, returns to her original location. What is the person’s:
a) overall distance travelled? b) overall displacement?
5. A car is moving at 74.0 km/h for 1.55 minutes. Determine the distance travelled. (Standard units)
6. A cyclist travels 640 m East in 41.0 seconds, and then travels 990 m West in 77.0 seconds. Determine: a) his average speed b) his average velocity
7. Identify the following quantities as scalar (S) or vector (V).
time ____ distance ____ displacement ____ speed _____ velocity ____ position ____ acceleration ____ force ____ work ____ energy _____ 8. An object starts in a location that is 6.0 m right of a rock. It then moves to a location 3.0 m left of
the rock, and finally, it moves to a location 8.0 m right of the rock.
a) Sketch a diagram of this motion. On this diagram, sketch the overall displacement vector. b) Determine the overall distance travelled.
Use the position-time and speed-time graphs to answer the following 5 questions.
9. Which graph(s) represents an object that is not moving? 10. Which graph(s) represents uniform motion?
11. Which graph(s) represents acceleration? 12. Which graph represents negative acceleration?
13. What is the velocity (magnitude) of the object in Graph II?
14. Determine the distance travelled by the object for the 1st 5 seconds for: a) Graph II b) Graph V (answer to 3 sig digs)
15. A rocket from liftoff reaches a velocity of 2000 m/s (from rest). If the magnitude of the rocket’s acceleration is 64.2 m/s2, then determine the time required for this motion.
Use the ‘ticker tape’ diagram below to answer the following 3 questions
This long ticker tape measures a dot every five seconds.
16. What type of motion is the object exhibiting?
17. Which graph(s) on the previous page best illustrates the tickertape motion?
18. By making measurements and using a scale ratio, determine the average speed of the object shown during the 1st 30 seconds.
1.00 m
distance (m) 50
40
10 30
2.00
Time (h) 20
A
B
C
D
1.00 3.00 4.00 5.00 6.00 7.00 8.00
Use the graph below to answer the next 4 questions
19. What type of motion is the object experiencing during B and D? 20. During which interval is the object
moving with the greatest speed? 21. What is the displacement of
the object after 8 hours? (mag)
22. What is the speed of the object during interval C?
Force, Work and Energy
23. The net force on a 300 g mass is 5.6 N. What is the magnitude of its acceleration?
24. A 12 kg object (at rest) experiences two forces: 50 N right and 30 N left. a) What is the net force (magnitude and direction)?
b) What is the acceleration (mag and dir)?
c) What is the velocity of the object after 4.0 seconds?
25. A 5.00 kg sled is being pulled forward at a constant velocity of 1.80 m/s for 6.80 seconds. The applied force is 30.0 N.
a) What is the displacement (mag and dir) of the sled?
b) Which of Newton’s laws applies here? So, what is the force of friction? c) What is the work done by friction during this motion?
26. a) A ball is lifted to a height of 10 m. It has a mass of 1.00 kg. What is the ball’s potential energy? b) If the ball falls from its maximum height, what is the kinetic energy just before it hits the ground?
Assume no air resistance.
c) What is its velocity just before it hits the ground?
d) Describe the energy conversion (transformations and transfers): (i) when it is lifted to a height of 10 m
(ii) when it is dropped (iii) when it hits the ground
Energy Systems and Conversions
27. a) A closed can of salmon can exchange energy with the environment but not matter. What type of system is this?
b) The can is opened. What type of system is it now?
Use the diagram below to answer the next 5 questions. Use terms such as potential energy, kinetic energy, electrical energy, generator and turbine.
28. At point A what is the type of energy? 29. What is the energy conversion
along B?
30. What is the machine that the water passes through to get to point C? 31. What is the machine located at D?
Use the diagram below to answer the next 5 questions. Use terms such as chemical energy, mechanical, electrical energy, and thermal energy
33. What type of energy is stored in coal? 34. What type of energy is released when coal
is burned?
35. The energy from steam is passed through a turbine, causing it to spin. What is the energy conversion?
36. The machine (generator) that the turbine is attached to converts energy into what form?
37. a) If coal produced 10,000 J of input energy and 2.0 kJ of output energy was produced, what was the efficiency of the engine?
b) What percentage of the energy is lost as waste? What type of energy would this be?
38. An engine is 31.0% efficient. If it produces 520 J of useful (mechanical) energy, then determine the input energy.
39. An average force of 80.0 N (from a person) is needed to compress a spring 0.150 m. The spring is oriented vertically and a 37.0 g ball is placed on top. The spring is then released and the ball is launched upward, and it continues to move upward until it reaches maximum height. Assume that the spring is only 64.0% efficient.
a) Describe the energy conversion: (i) when compressing the spring (ii) when the spring is released (iii) when it moves up to max height
b) Determine how much spring energy is stored within the spring. (Hint: Find the work done)
40. A horizontal force is applied to a 3.0 kg object that is initially at rest. Its nature is summarized using the graph shown. a) Determine the work done on
the 3.0 kg mass.
b) Determine the maximum speed
attained by the 3.0 kg mass, assuming a level surface.
SOLUTIONS
1. a) 4 b) 2 2. a) 25.0 g b) 1.00 × 103 m3 3. a) 1.283 m/s b) 42.5 km/h 4. a) 160 m b) 0
5. 20.556 m/s , 93 s , 1.91 103 m 6. a) 13.8 m/s b) 2.97 m/s West 7. S, S, V, S, V, V, V, V, S, S
8. b) 20.0 m c) 2.0 m right a) 9. I 10. I and II
11. III, IV, and V 12. IV
13. 10 m/s 14. a) 50.0 m b) Area = 125 m
15. 31.2 s 16. accelerated motion 17. III and V 18. 6.19 m ; 30 s ; 0.206 m/s 19. At rest 20. A
21. Area = 105 m 22. Slope = 5.00 m/h 23. 0.300 kg ; 19 m/s2 24. a) 20 N right b) 1.7 m/s2 right c) 6.7 m/s right
25. a) 12.2 m forward b) 30.0 N backwards (1st law) c) 367 J 26. a) 98.1 J b) 98.1 J c) 14.0 m/s
d) (i) Potential energy in person Epg in object + heat/sound (ii) Epg in object Ek in object
(iii) Ek in object deforming ground + heat/sound
27. a) closed b) open 28. Epg 29. Epg to Ek 30. turbine 31. generator 32. Ek to Electrical
33. chemical energy 34. chemical to thermal energy 35. thermal to mechanical energy 36. mechanical energy to electrical energy
37. a) 20% b) 80% as heat 38. 1.68 kJ
39. a) Compress spring: Potential energy in person Es in spring + heat Release spring: Es in spring Ek in ball
Up to max h: Ek in ball Epg in ball b) 12.0 J c) 0.0370 kg ; 21.2 m 40. a) Area = 12 J b) 2.8 m/s
F (N)
