2. Work and Energy 5. What is a force? a. change in speed over time b. the tendency to resist change in motion c. a push or pull d. apparent weightlessness

3. Work and Energy 5. What is a force? a. change in speed over time b. the tendency to resist change in motion c. a push or pull d. apparent weightlessness

4. Work and Energy 9. What is the result of a net force acting on an object? a. the object will accelerate b. the object remain motionless c. the object’s velocity will not change d. inertia is greater than net forces

5. Work and Energy 9. What is the result of a net force acting on an object? a. the object will accelerate b. the object remain motionless c. the object’s velocity will not change d. inertia is greater than net forces

6. Work and Energy Which of the following does NOT represent work being done. a. You lift a 4 kg box 1.5 m to the table. b. You pull a wagon 10 meters. c. You hold the door open for your mom. d. You push a desk across the floor.

7. Work and Energy Which of the following does NOT represent work being done. a. You lift a 4 kg box 1.5 m to the table. b. You pull a wagon 10 meters. c. You hold the door open for your mom. Why? d. You push a desk across the floor.

8. Work and Energy Which of the following does NOT represent work being done. c. You hold the door open for your mom. Why? Even though you apply force to to keep the door open, the door does not move.

9. Work and Energy The amount of work done in a specified amount of time is called a. joules b. resistance c. power d. Mechanical advantage

10. Work and Energy The amount of work done in a specified amount of time is called a. joules b. resistance c. power d. Mechanical advantage

11. Work and Energy An object that is only acting under the influence of gravity is ___________ a. decelerating b. in free fall c. stationary d. weightless

12. Work and Energy An object that is only acting under the influence of gravity is ___________ a. decelerating b. in free fall c. stationary d. weightless

13. Work and Energy For every force there is an equal and opposite reaction force is a. Newton's 1 st Law of Motion b. Newton's 2 nd of Motion c. Newton's 3 rd Law of Motion d. Newton's 4 th Law of Motion

14. Work and Energy For every force there is an equal and opposite reaction force is a. Newton's 1 st Law of Motion b. Newton's 2 nd of Motion c. Newton's 3 rd Law of Motion d. Newton's 4 th Law of Motion

15. Work and Energy What is the gravitational acceleration constant on earth? a. 9.8 m/s b.98 m/s c.9.8 m/s 2 d.982 mph

16. Work and Energy What is the gravitational acceleration constant on earth? a. 9.8 m/s b.98 m/s c.9.8 m/s 2 d.982 mph

17. Work and Energy Which state of matter is completely compressed, retains its shape, and represents the lowest form of kinetic energy among its molecules? Drop of a Bullet

18. Work and Energy Which state of matter is completely compressed, retains its shape, and represents the lowest form of kinetic energy among its molecules? solids Drop of a Bullet

19. Work and Energy What is the equation for calculating kinetic energy? Drop of a Bullet

20. Work and Energy What is the equation for calculating kinetic energy? KE = ½ mv 2 OR Drop of a Bullet

21. Work and Energy Kinetic energy is expressed in what units? Drop of a Bullet

22. Work and Energy Energy is measured in what units? Joules J Drop of a Bullet

23. Work and Energy What is the kinetic energy of a 5kg object traveling at 10m/s? Drop of a Bullet

24. Work and Energy What is the kinetic energy of a 5kg object traveling at 10m/s? KE = ½ mv 2 KE = 5kg x (10m/s) 2 2 = 250 J Drop of a Bullet

25. Work and Energy What is the equation for calculating gravitational potential energy? Drop of a Bullet

26. Work and Energy What is the equation for calculating potential energy? PE = mgh What do the letters stand for?

27. Work and Energy What is the equation for calculating potential energy? PE = mgh What do the letters stand for? m = mass g = gravity (9.8m/s 2 ) h = height of the object in m

28. Work and Energy A 1.5 kg coconut hangs in a palm tree? How much gravitational potential energy does the coconut have if the tree is 15 meters tall? Drop of a Bullet

29. Work and Energy A 1.5 kg coconut hangs in a palm tree? How much gravitational potential energy does the coconut have if the tree is 15 meters tall? PE = mgh = (1.5 kg)(9.8m/s2)(15 m) 220 J Drop of a Bullet

30. Work and Energy A rollercoaster car with a mass of 500 kg has 600 J of potential energy. How tall is the rollercoaster? PE = mgh so = 600 kJ/(9.8m/s 2 x 500kg) = 122 m Drop of a Bullet

31. Work and Energy What is the mechanical energy of a 40 kg child swinging at the moment her velocity is 20 m/s and she is 2 m off of the ground? Drop of a Bullet

32. Work and Energy What is the mechanical energy of a 40 kg child swinging at the moment her velocity is 20 m/s and she is 2 m off of the ground? Hint: Mechanical Energy = KE + PE Calculate each and sum. Drop of a Bullet

33. Work and Energy Calculate the mechanical energy of a 40 kg child swinging at the moment her velocity is 20 m/s and she is 2 m off of the ground? Hint: Mechanical Energy = KE + PE Drop of a Bullet

34. Work and Energy Calculate the mechanical energy of a 40 kg child swinging at the moment her velocity is 20 m/s and she is 2 m off of the ground? Hint: Mechanical Energy = KE + PE Drop of a Bullet

35. Work and Energy What is the mechanical energy of a 40 kg child swinging at the moment her velocity is 20 m/s and she is 2 m off of the ground? PE = mgh so = 600 kJ/(9.8m/s 2 x 500kg) = 122 m Drop of a Bullet