1. The Newton is a unit of

energy force mass momentum none of these Useful Web Links The Unit "Newton" (7 seconds)

2. A(n) ___________ quantity is completely described by its size and direction.

Useful Web Links Scalars and Vectors (3 seconds)

For questions #3-4, consider the graph shown below:

3. Describe the motion of the object depicted in the above graph.

Useful Web Links The Meaning of Shape for a p-t Graph (14 seconds)

4. Construct a velocity vs. time graph for the above motion.

Useful Web Links The Meaning of Shape for a p-t Graph (14 seconds) The Meaning of Shape for a v-t Graph (8 seconds)

The Meaning of Shape for a v-t Graph (8 seconds)

Consider the graph on the right for questions #5-7:

5. Verbally describe the motion of the object depicted by the above graph .

Useful Web Links The Meaning of Shape for a v-t Graph (8 seconds)

6. Determine the total displacement of the object during the 15 seconds.

Useful Web Links Determining the Area on a v-t Graph (12 seconds)

7. Draw the acceleration vs. time graph that is derived from the graph above.

Use the ticker tapes for questions #8-10.

8. Which tape(s) show(s) acceleration?

A B C Useful Web Links Ticker Tape Diagrams (6 seconds) Acceleration (12 seconds) Depress mouse to view answer. Answer: Both A and B Acceleration is a change in velocity. For a "ticker tape diagram," this is depicted by a changing distance between each consecutive dot.

Acceleration (12 seconds)

9. Which tape(s) show(s) negative acceleration?

A B C Useful Web Links Ticker Tape Diagrams (6 seconds) Acceleration (12 seconds)

10. Which tape shows constant speed?

A B C Useful Web Links Ticker Tape Diagrams (6 seconds) Speed and Velocity (8 seconds)

Speed and Velocity (8 seconds)

11. A ball thrown upward with a velocity of 25 m/s will go in the upward direction for about ______ seconds.

25 2.5 5.0 4.3 none of these Useful Web Links Kinematic Equations and Problem-Solving (7 seconds) Kinematic Equations and Free Fall (8 seconds)

Kinematic Equations and Free Fall (8 seconds)

12. You (accidentally of course) drop your cat from the roof (of a very tall building). If it starts from rest and takes the cat 4.6 seconds to reach the ground (Hint: use the acceleration of gravity)...

... how fast is the poor cat going when it hits the ground (where very rapid deceleration occurs)? Useful Web Links Kinematic Equations and Problem-Solving (7 seconds) Kinematic Equations and Free Fall (8 seconds)

... how tall is the building? Useful Web Links Kinematic Equations and Problem-Solving (7 seconds) Kinematic Equations and Free Fall (8 seconds)

13. A 5.0-kg rock is thrown up vertically. Draw the free-body diagram on the rock during its trajectory.

Useful Web Links What is a Projectile? (11 seconds)

For questions #14-16 consider a projectile thrown horizontally at 50 m/s from a height of 19.6 meters.

14. The projectile will take _____ time to hit the ground as it would if it were dropped from the same height

More Less The same Useful Web Links Characteristics of a Projectile's Trajectory (12 seconds) Depress mouse to view answer. Answer: c Having a horizontal velocity will not effect the time to fall vertically. Perpendicular components of motion do not effect each other.

Depress mouse to view answer. Answer: c Having a horizontal velocity will not effect the time to fall vertically. Perpendicular components of motion do not effect each other.

15. The projectile will be in the air

1.0 seconds 2.0 seconds 3.0 seconds 4.0 seconds Useful Web Links Horizontally Launched Projectiles - Problem-Solving (10 seconds) Depress mouse to view answer. Answer: b The only parameters effecting the time to fall vertically are vertical parameters of motion. Thus, using the equation that y = viy*t + 0.5*a*t^2 and substituting with viy=0 m/s (initially, the ball's vert. vel. is 0), a=-9.8 m/s/s (the accel'n is the value of g), y=-19.6 m (the ball falls 19.6 m), one finds that t = 2.0 s

Depress mouse to view answer. Answer: b The only parameters effecting the time to fall vertically are vertical parameters of motion. Thus, using the equation that y = viy*t + 0.5*a*t^2 and substituting with viy=0 m/s (initially, the ball's vert. vel. is 0), a=-9.8 m/s/s (the accel'n is the value of g), y=-19.6 m (the ball falls 19.6 m), one finds that t = 2.0 s

16. The projectile will cover a horizontal distance of ____ meters

50 100 150 200 Useful Web Links Horizontally Launched Projectiles - Problem-Solving (10 seconds) Depress mouse to view answer. Answer: b The only parameters effecting the horizontal motion are horizontal parameters of motion. If the ball is moving horizontally for 2.0 seconds (from previous problem) at a constant horizontal speed of 50 m/s (given in the problem statement), then it will cover (50 m/s)*(2 s) or 100 m. This is from the eq'n x = vix*t.

Depress mouse to view answer. Answer: b The only parameters effecting the horizontal motion are horizontal parameters of motion. If the ball is moving horizontally for 2.0 seconds (from previous problem) at a constant horizontal speed of 50 m/s (given in the problem statement), then it will cover (50 m/s)*(2 s) or 100 m. This is from the eq'n x = vix*t.

17. Given the net forces (F) upon the objects below and the resulting acceleration (a) of each which of the objects below has the greatest inertia?

Useful Web Links Inertia and Mass (12 seconds) Newton's Second Law (9 seconds)

Newton's Second Law (9 seconds)

18. If it is known that an unbalanced force is acting upon an object, then which of the following MUST be true regarding the object's motion? The object is:

at rest being accelerated losing mass moving at a constant speed Useful Web Links Balanced and Unbalanced Forces (7 seconds) The Big Misconception (9 seconds)

The Big Misconception (9 seconds)

19. A 750 Newton person stands upon the floor. Considering action/reaction, what is the reaction force to the person's weight?

The floor pushing up on the person with 750 Newtons of force The person pulling up on the earth with 750 Newtons of force 0 N since the object wasn't accelerating 1500 Newtons, since there is a total force of 1500 Newtons acting. Useful Web Links Identifying Action and Reaction Force Pairs (6 seconds)

20. A spiraled tube lies fixed in its horizontal position (i.e., it has been placed upon its side upon a table). When a marble is rolled through it it curves around the tube, draw the path of the marble after it exits the tube.

Useful Web Links Newton's First Law (10 seconds) Speed and Velocity (6 seconds)

Speed and Velocity (6 seconds)

Superman came from a planet (Krypton) which had an acceleration of gravity of 88 m/s/s. He weighs 833 Newtons on earth.

21. Superman's mass on Krypton would be ___ kg.

9.8 85 833 7480 Useful Web Links Mass vs. Weight (8 seconds) Depress mouse to view answer. Answer: b If he weighs 833 N on Earth, then his mass on Earth can be found by dividing the Weight by the acceleration of gravity on Earth - 9.8 m/s/s (recall the equation Fgrav = m*g).

Depress mouse to view answer. Answer: b If he weighs 833 N on Earth, then his mass on Earth can be found by dividing the Weight by the acceleration of gravity on Earth - 9.8 m/s/s (recall the equation Fgrav = m*g).

22. Superman's weight on Krypton would be ____ N.

9.8 85 833 7480 Useful Web Links Mass vs. Weight (8 seconds) Depress mouse to view answer. Answer: d If Superman has a mass of 85 kg on Earth, then he also has a mass of 85 kg on Krypton. His weight on Krypton can be found by multiplying his mass by the acceleration of gravity on Krypton - given as 88 m/s/s (recall the equation Fgrav = m*g).

Depress mouse to view answer. Answer: d If Superman has a mass of 85 kg on Earth, then he also has a mass of 85 kg on Krypton. His weight on Krypton can be found by multiplying his mass by the acceleration of gravity on Krypton - given as 88 m/s/s (recall the equation Fgrav = m*g).

23. A 75-kg object dropped over a large vertical distance. After 13 seconds of falling, the object experiences an upward force of air resistance of 550 Newtons. The acceleration of the object 13 seconds after being dropped is ____ m/s/s

0 2.5 9.8 735 Useful Web Links Finding Acceleration (6 seconds)

For questions #24-26 use the following situation. A 60.0-gram golf ball was struck by one of GBS' golf team members. The impact lasted for 0.0015 seconds and the ball flew off the tee at 45 m/s.

24. The impulse experienced by the ball was ___ kg*m/s

0 2.7 45 1800 Useful Web Links Momentum and Impulse Connection (14 seconds) Depress mouse to view answer. Answer: b Impulse can be found two ways: 1. Use the definition of impulse as F*t and known values of F and t (if given), or 2. Use the impulse-momentum change theorem which says Impulse=change in momentum. The second method is used here to find that the ball's momentum change is m*delta v or 0.060 kg*(45 m/s-0 m/s) = 2.7 kg*m/s.

Depress mouse to view answer. Answer: b Impulse can be found two ways: 1. Use the definition of impulse as F*t and known values of F and t (if given), or 2. Use the impulse-momentum change theorem which says Impulse=change in momentum. The second method is used here to find that the ball's momentum change is m*delta v or 0.060 kg*(45 m/s-0 m/s) = 2.7 kg*m/s.

25. The net force exerted upon the ball was ____ Newtons.

0 2.7 45 1800 Useful Web Links Momentum and Impulse Connection (14 seconds) Depress mouse to view answer. Answer: d Use the impulse-momentum change theorem which says Impulse=change in momentum or in terms of symbols, F*t=m*delta v. Solve this equation for force (F).

Depress mouse to view answer. Answer: d Use the impulse-momentum change theorem which says Impulse=change in momentum or in terms of symbols, F*t=m*delta v. Solve this equation for force (F).

26. If the club head a mass of 540 grams, the net force exerted upon the golf club was ____ Newtons.

0 2.7 45 1800 Useful Web Links The Law of Action-Reaction (Revisited) (8 seconds)

27. The coefficient of kinetic friction for wood on wood is 0.22. The applied force that would be necessary to pull a 35 kg wood block across a wooden floor at a constant speed is ___ Newtons.

0 0.22 35 75 Useful Web Links Friction and Coefficient of Friction (8 seconds) Finding Individual Forces (7 seconds) Depress mouse to view answer. Answer: d Begin with a free-body diagram and then recognize that the two horizontal forces - friction and applied - must be equal in magnitude in order to maintain the constant speed. Friction's value is mu*Fnorm where mu=0.22 (given) and Fnorm is the same as the object's weight (approx. 350 N, found from m*g). Thus, Ffrict = 0.22*350 N = 75 N (approx.). Fapp must also be 75 N.

Finding Individual Forces (7 seconds)

Depress mouse to view answer. Answer: d Begin with a free-body diagram and then recognize that the two horizontal forces - friction and applied - must be equal in magnitude in order to maintain the constant speed. Friction's value is mu*Fnorm where mu=0.22 (given) and Fnorm is the same as the object's weight (approx. 350 N, found from m*g). Thus, Ffrict = 0.22*350 N = 75 N (approx.). Fapp must also be 75 N.

28. The resultant of the two vectors is best represented by:

Useful Web Links Vector Addition (20 seconds) Resultants (6 seconds)

Resultants (6 seconds)

29. The best representation of the relationship between force and acceleration is:

Directly Force and acceleration are directly related Net force is directly related to acceleration Acceleration is directly related to net force All of the these are equivalent Useful Web Links Newton's Second Law (9 seconds) Depress mouse to view answer. Answer: d This is nothing more than Newton's second law of motion, sometimes expressed in equation form as a = Fnet/m In words: "Acceleration depends directly upon the net force acting upon an object ..."

Depress mouse to view answer. Answer: d This is nothing more than Newton's second law of motion, sometimes expressed in equation form as a = Fnet/m In words: "Acceleration depends directly upon the net force acting upon an object ..."

30. In the movie "Crocodile Dundee" Dundee grabs a rope with his bare hands, drops a few stories, and stops relatively instantly and crashes through a window. Using momentum, what is wrong with this scene?

Useful Web Links Momentum and Impulse Connection (14 seconds) Real-World Applications (15 seconds)

Real-World Applications (15 seconds)

31. Momentum is defined as:

Changing speed Mass in motion Accelerating Force times time Useful Web Links Momentum (7 seconds) Depress mouse to view answer. Answer: b This is just the textbook's definition.

Depress mouse to view answer. Answer: b This is just the textbook's definition.

Smackin D. Face is riding his bike at a high speed when he encounters a moth in a gruesome head-on collision. The unfortunate moth is about to meet Smackin's Goggles. For questions #32-34 below, consider the moth-Smackin collision.

32.Which object (Smackin or the moth) experiences the largest force?

Smackin The Moth They both experience the same Useful Web Links The Law of Action-Reaction (Revisited) (8 seconds) Momentum Conservation Principle (16 seconds) Depress mouse to view answer. Answer: c According to Newton's law of action-reaction, in any collision, the interaction between the colliding objects results in mutual forces upon the two interacting objects which are equal in magnitude and opposite in direction.

Momentum Conservation Principle (16 seconds)

Depress mouse to view answer. Answer: c According to Newton's law of action-reaction, in any collision, the interaction between the colliding objects results in mutual forces upon the two interacting objects which are equal in magnitude and opposite in direction.

33. Which object (Smackin or the moth) experiences the greatest change in momentum?

Smackin The Moth They both experience the same Useful Web Links The Law of Action-Reaction (Revisited) (8 seconds) Momentum Conservation Principle (16 seconds) Depress mouse to view answer. Answer: c If each object experiences the same force (previous question) and if the forces act for the same amount of time (as they do in any interaction), then each object experiences the same impulse. Since impulse equals the momentum change, each object must therefore experience the same momentum change. (Did you notice the use of logic and reasoning here?)

Depress mouse to view answer. Answer: c If each object experiences the same force (previous question) and if the forces act for the same amount of time (as they do in any interaction), then each object experiences the same impulse. Since impulse equals the momentum change, each object must therefore experience the same momentum change. (Did you notice the use of logic and reasoning here?)

34. Which object (Smackin or the moth) experiences the largest change in velocity?

Smackin The Moth They both experience the same Useful Web Links The Law of Action-Reaction (Revisited) (8 seconds) Momentum Conservation Principle (16 seconds)

35. Moving at 20.0 m/s, a car of mass 710 kg collides head on with a stationary truck of mass 1400 kg. If the two vehicles interlock as a result of the collision, then what is the velocity of the car-truck system after the collision?

6.7 m/s 20 m/s 710 m/s Useful Web Links Collisions - Problem-Solving (12 seconds)

36. A 0.50-kg ball traveling at 6.0 m/s collides head on with a 1.00-kg ball at rest. The 0.50-kg ball moves away traveling opposite to its original direction at 2.0 m/s after the collision. Find the velocity of the 1.00-kg ball after the collision

2.0 m/s 4.0 m/s 6.0 m/s 8.0 m/s Useful Web Links Collisions - Problem-Solving (12 seconds)

37. If a person jumps twice as high on a trampoline, ...

she will have twice the potential energy at the top of her jump. she will have started with twice the kinetic energy at the begining of her jump. she will have four times as much potential energy at the top of her jump. Useful Web Links Potential Energy (12 seconds) Kinetic Energy (4 seconds)

Kinetic Energy (4 seconds)

38. A person jumps on a trampoline. If the person reaches a height above the trampoline of 0.350 meters, with what velocity did the person leave the trampoline? (Hint: mass cancels from the work-energy equation)

0.35 m/s 0.85 m/s 6.9 m/s 2.6 m/s none of these Useful Web Links Work-Energy Theorem - Problem-Solving (13 seconds)

39. A 50.0-kg sack is lifted 2.0 meters in the same time a 25.0-kg sack is lifted 4.0 meters. The power expended in raising the 50-kg sack as compared to the power used to lift the 25-kg sack is:

Twice as much Half as much The same Useful Web Links Power (13 seconds)

40. Since the earth is attracted to the sun, why doesn't it fall into the sun?

Because it has a large tangential velocity. Because there is an equal force holding it away from the sun. Because it has too much mass to move towards the sun. Because it has too much inertia to move toward the sun. Useful Web Links The Apple, the Moon, and the Inverse Square Law (12 seconds) Circular Motion Principles for Satellites (10 seconds) Depress mouse to view answer. Answer: a While the "Earth falls towards the Sun," it never collides with it due to the fact that there is a large tangential velocity. The inward force of gravity on the Earth merely causes it to deviate from its straight-line path and "continously curve towards the Sun."

Circular Motion Principles for Satellites (10 seconds)

Depress mouse to view answer. Answer: a While the "Earth falls towards the Sun," it never collides with it due to the fact that there is a large tangential velocity. The inward force of gravity on the Earth merely causes it to deviate from its straight-line path and "continously curve towards the Sun."

41. A 1350 kg car traveling at 16 m/s rounds a curve of radius 212 meters.

...What is the size and direction of the centripetal acceleration? Useful Web Links Acceleration (10 seconds) Mathematics of Circular Motion (9 seconds)

Mathematics of Circular Motion (9 seconds)

...What is the size and direction of the net force? Useful Web Links The Centripetal Force Requirement (14 seconds) Mathematics of Circular Motion (9 seconds)

...What is the minimum force of friction between the tires and the road? Useful Web Links Newton's Second Law and Circular Motion (12 seconds)

42. In which case is the force greatest on the arms of the hanging person?

Useful Web Links Equilibrium and Statics (23 seconds)

Question #4

Return to Question 4

Question #7

Return to Question 7

Question #13

NOTE: Even as the projectile is rising, the only force acting upon is the downward force of gravity. The projectile rises only because it still has an upward velocity. This upward velocity is continuously decreasing as gravity acts upon the object.

Question #20

NOTE: the marble leaves tangent to the circle in a straight-line, inertial path.

Return to Question 20

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This page last updated on January 4, 1999.