Name period date assigned date due date returned. Work or No Work?

Transcription

1 Name period date assigned date due date returned? Directions or each activity diagram the situation. Make sure you show arrows for your force and the direction of motion of the object. Activity 1 Apply a quick push to the block of wood to make it move 100cm. Activity 2 Apply a force to the block to lift it 100cm. Activity 3 Apply a constant push to the block to move it 100cm Activity 4 Hold a block at the same level for 15 seconds Activity 5 Apply a constant downward force to the desk for 15 seconds Activity 6 Apply a pull to the block to make it move 100cm. 1

2 Ramp or No Ramp Read the instructions for the activity from the power point. Results 7. orce needed to lift the block straight up 8. Height the block was lifted..5m 9. orce needed to pull the block up the inclined plane 10. Length of the inclined plane.5m 11. orce needed to pull the block up the lower inclined plane 12. Length of the inclined plane.5m alculate the amount of work done in each situation WORK = ORE x DISTANE without an inclined plane with an steep inclined plane with an lower inclined plane Questions 13. What are some examples of force? 14. Does applying a force always cause a change in position? 15. Does a change in position always involve a force? 16. Does work always involve a force? 17. Does work always involve a change in position? 18. Explain how an inclined plane affected the amount of work done. 2

3 19 Identify a situation in which work is being done. A turning a page in a science book B reading a science book resting a science book against the wall 20 What evidence proves that no work is being done on an object? an object remains stationary G an object moves H an object has mass an object is heavy D holding a science book 21 A batter walks up to home plate with his bat, stands with his bat in the air, swings his bat, and makes contact with the ball. In which part of this situation is NO work occurring? A B D batter walks up to home plate with his bat batter stands with his bat in the air batter swings the bat batter makes contact with the ball 3

4 22 Work is the product of force and time G power H distance speed 23 Which of the following choices best represents force? A a push or a pull always causing motion B a push or a pull always causing acceleration a push or a pull acting without an object D a push or a pull acting on an object 24 A scientist can calculate the amount of work done by using the equation - w = x d G w = x H w = N x m w = x d 25 A 500-newton girl lifts a 10- newton box vertically upward a distance of 0.5 meters. The work done on the box is - A 5 B D

5 26 An unbalanced force can cause an object s motion to change by changing direction or speed; starting, but not stopping motion G changing direction or speed, starting or stopping motion H changing direction or speed; stopping, but not starting motion changing direction or speed only 27 A sheet of notebook paper lying motionless on a table and not touched by an outside force will MOST likely remain motionless because - A balanced forces exerted by gravity and the table keep the paper motionless B an unbalanced force is exerted by the table to keep the paper motionless balanced forces exerted by gravity and the air keep the paper motionless D an unbalanced force is exerted by the air to keep the paper motionless 28 Two boxes and their masses are shown below. Which of the following situations shows work being done? G H A student is sitting in a chair and holding both boxes. A student is holding the large box 1m above the floor. A student is standing and holding the small box. A student is lifting the small box 0.5m from the floor to a table 5

6 Use the following data from a force experiment to make a conclusion. 29 Trial 1: when the ramp was set at 90 degrees, it took 10N of force to move the 1 kg object. Trial 2: when the ramp was set at 60 degrees, it took 8.6N of force to move the 1 kg object. Trial 3: when the ramp was set at 30 degrees, it took 5N of force to move the 1 kg object. irst, label the diagrams for trial 2 and 3 to illustrate these results. Trial 1 has already been done for you as an example. Trial 1 Trial 2 Trial 3 10N 90 1 kg What conclusion can you make from this data? Make sure you write in complete sentences. 6

7 Extension: The equation for work is: work= force x distance Using this equation, calculate how much work is being done in each situation. Remember, the unit for work is joules (). 30. A man is pushing on a wall with 50N of force. The wall does not move (0m). How much work is he doing? 31. A boy pedaled his bike for 1500m and used a total of 100N of force. How much work did he do? 32. Two friends went on a boat ride on the Nueces River. One boy did most of the rowing. He rowed for 300m and used 75N of force. How much work did he do? 33. The GWH cheerleaders were doing a lift. The girl in the middle used 43N of force to hold up the other girl. Once up on her shoulders, the girl did not move at all (0m). How much work was done? 7