8 th Science Force, Motion, and Energy

Transcription

1 8 th Science Force, Motion, and Energy

2 #1 What is speed plus direction? Example: Geese fly about 64 km/hr when they migrate south. A: Force B: Weight C: Acceleration D: Velocity

3 D. Velocity

4 #2 A push or pull. A: Force B: Weight C: Acceleration D: Air resistance

5 A. Force

6 #3 What is a change in motion? (Speeding up, slowing down, changing direction). Example: An airplane slows 2 down at a rate of 3 m/s A: Acceleration B: Air resistance C: Friction D: Inertia

7 A. Acceleration

8 #4 What is the relationship between force, motion, and energy? A: It takes energy to B: make force Force causes motion C: Neither D: Both

9 D. Both A and B

10 #5 A force that resists motion. A: Air resistance B: Friction C: Inertia D: Force

11 B. Friction

12 #6 A measure of an object s tendency to remain at rest or to keep moving with a constant velocity. A: Air resistance B: Inertia C: Force D: Newton

13 B. Inertia

14 #7 Forces occur in pairs and each pair of forces can be either balanced or unbalanced. How can an unbalanced force change the speed or direction of an object in motion? One of the forces is A: B: stronger than the other Both forces are equal Unbalanced forces C: cancel each other out, D: so there is no change Force

15 A. One of the forces is stronger than the other

16 #8 Which unit measures the Unit of Force? A: Newtons B: Meters C: Seconds D: m/s 2

17 A. Newtons

18 Ex: Seat belt Ex: pulling the table cloth out from under dishes #9 An object a rest remains at rest and an object in motion remains in motion at a constant speed unless acted upon by a unbalanced force. A: Law 1 Law of Inertia B: Law 2 Law of Acceleration C: Law 3 Law of Action D: and Reaction Law 4 Law of Conservation

19 A.Law 1 Law of Inertia

20 #10 An object acted on by an unbalanced force will accelerate in the direction of the force. Ex: It takes more force to move a car than a bicycle *(More force is required to move more mass.) A: Law 1 Law of Inertia B: Law 2 Law of Acceleration C: Law 3 Law of Action D: and Reaction Law 4 Law of Conservation

21 B. Law 2 Law of Acceleration

22 Ex: Rocket launching. #11 Every action has an equal and opposite reaction. A: Law 1 Law of Inertia B: Law 2 Law of Acceleration C: Law 3 Law of Action D: and Reaction Law 4 Law of Conservation

23 C. Law 3 Law of Action and Reaction

24 #12 Measure Speed What is your speed if you travel 114 km in 3 hours? Speed = Distance Time A: S = 38 km/hr B: S = 38 hrs C: S = 38 km D: S = 3 km/hr

25 A. S = 38 km/hr

26 #13 Measure Force What force is needed 2 to make a 36 kg object accelerate to 5 m/s? Force = mass x acceleration A: F = 180 kg B: F = 180 N C: F = 108 N D: F = 180 m/s 2

27 B. F = 180 N

28 #14 How does force effect work? Work = Force x Distance (if no distance, no work) How much work would it take to move a 50 N box over 6 meters? A: W = 300 N B: W = 300 M C: W = 300 j D: W = 300 km

29 C. 300 j

30 #15 Why can a spacecraft travel in space at a constant speed and in a straight path? A: There is no force or B: gravity There is no friction or gravity C: There is no friction or D: newton There is no weight or mass

31 B. There is no friction or gravity

32 #16 Calculating net force. What would be the net force in this diagram? 16N 10N = 6N Box will move to the A: B: left 6N Box will move to the right 6 N C: The force is balanced D: None of these

33 A. Box will move to the left 6N

34 #17 This graph relates distance to time for a jogger. Distance vs. Time At what rate of speed is Juan running between 4 min and 6 min? S= 500m/2min A: 150m/s B: 250m/s C: 1400m/s D: None of these

35 B. 250m/s

36 #18 This graph relates distance to time for a jogger. Distance vs. Time What can you tell about Juan s motion between 7 and 11 min? A: Stopped B: Ran faster C: Jogging slower D: None of these

37 A. Stopped

38 #19 What is potential energy? A: Motion energy B: Stored energy C: Electrical energy D: None of these

39 B. Stored energy

40 #20 What is kinetic energy? A: Motion energy B: Stored energy C: Electrical energy D: None of these

41 A. Motion energy

42 #21 How are potential energy and kinetic energy related? Energy can convert A: from kinetic to B: potential and back again They are not related C: Both are energy in D: motion None of these

43 A. Energy can convert from kinetic to potential and back again

44 #22 Which of these graphs shows a speed that is not changing (constant speed) A: B: Graph A Graph B C: Graph C D: None of these

45 C. Graph C

46 Great Job!!!! Thank you for playing!