Name: Class: S2 Physics Forces Pupil Booklet Learning Outcomes Homework Exercises Unit Summary SCN 3-07a By contributing to investigations of energy loss due to friction, I can suggest ways of improving the efficiency of moving systems. SCN 3-08a I have collaborated in investigations into the effects of gravity on objects and I can predict what might happen to their weight in different situations on Earth and in space. Page 1
How Confident am I with the Learning Outcomes? Circle the faces to keep a record of your progress. I am confident that I understand this and I can apply this to problems I have some understanding but I need to revise this some more I don t know this or I need help because I don t understand it You can use this to help you pick the areas of the unit that need the most revision. As you revise your class work you will be able to circle more and more smiley faces. If that does not help then you should ask your teacher! Learning Outcomes 1. State that a force can: a. Change the speed of an object. b. Change the direction of an object. c. Change the shape of an object. 2. Describe an example of: a. An object s speed being changed by a force. b. An object s direction being changed by a force. c. An object s shape being changed by a force. Can you do this? Comments 3. State that pushing, pulling, twisting and tearing are contact forces. 4. Identify which contact forces are present in different situations. Page 2
5. State that force is measured in Newtons (N). 6. State that force can be measured using a Newton Balance (force meter). 7. Use a Newton Balance to measure force. 8. State that there are 1000 grams (g) in 1 kilogram (kg). 9. State that mass is the amount of stuff in an object, measured in kilograms (kg). 10. State that weight is the pull of gravity on an object, measured in Newtons (N). 11. Use the formula, weight = 10 x mass, to convert mass to weight. 12. Draw a line graph of force (y-axis) against mass (x-axis). 13. State that weight is a force measured in Newtons (N). Page 3
14. State that three non-contact forces are: a. The force of gravity (gravitational pull of the Earth). b. Magnetic force. c. Electrostatic force. 15. Carry out experiments using noncontact forces. 16. State that charged polythene rods repel one another. 17. Identify which non-contact forces are present in different situations. 18. Explain how an electromagnet works. 19. Be able to assemble an electromagnet. 20. Give examples of gadgets which use electromagnets. 21. State that an electromagnet can be made stronger by: a. Increasing the number of turns on the coil. b. Increasing the number of batteries. 22. State that the force of friction is a contact force which slows down an object s movement. Page 4
23. State that the force of friction is caused by two surfaces rubbing together. 24. State that the force of friction acts in the opposite direction to the object s motion. 25. State that heat (and sound) is produced by the force of friction. 26. Carry out an investigation to find out how the force of friction is affected by the type of surface. 27. Interpret information relating to friction presented on a bar graph. 28. Describe how the force of friction can be reduced. 29. Describe how the force of friction can be useful. 30. Draw a line graph of overall stopping distance (y-axis) against speed of car (x-axis). 31. State that balanced forces are equal in size but opposite in direction. 32. State that when there are balanced forces acting on an object it will remain stationary or continue to move at constant (steady) speed. Page 5
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33. State that when the forces acting on an object are not balanced there is an unbalanced force. 34. State that unbalanced forces cause an object to accelerate (speed up) or decelerate (slow down). 35. Use your knowledge of balanced and unbalanced forces to determine the...(pto) motion of an object. 36. Use your knowledge of balanced and unbalanced forces to calculate the unbalanced (overall, total) force. 37. Give examples of balanced and unbalanced forces. 38. Identify balanced and unbalanced forces. 39. State that the lever is a machine that allows us to increase the size of a force. 40. Give examples of levers in everyday life. 41. Carry out an experiment, using a balance (see-saw), to establish the law of the lever. Page 7
42. Know that the law of the lever states: The force (F L ) x distance (d L ) on the left side of the see-saw = The force (F R ) x distance (d R ) on the right side of the see-saw. 43. Carry out calculations using the law of the lever. 44. State that forces can damage objects. 45. Identify important properties of a material. 46. Chose a material for a job based on its properties. 47. Identify the forces a material needs to withstand in use. 48. Carry out an investigation into the strength of sticky tape. 49. Use ICT to research and report on artificial joints. 50. View and extract information from prerecorded programmes related to force and friction, and forces related to sport. Page 8
Forces Homework 1 Contact Forces and the Force meter 1. A force can change the speed of an object. What other two things can a force change about an object? 2. Name the four contact forces you have learned about. 3. Write down the main contact force used in the following situations: (a) (b) (c) (d) Winding up a watch. Going through a revolving door. Closing the curtains. Ripping open a chocolate bar. 4. What device is used to measure force? 5. The unit for length is metres (m), what is the unit for Force? 6. The weight of a 3kg mass on Earth can be calculated like this: Calculate the weight of the following objects making sure that you show all working: (a) (b) 5kg mass. 8kg mass. Weight = 10 x mass = 10 x 3 = 30N 7. Copy the following statement and complete the blanks: is the amount of matter in an object measured in. is the pull of gravity on an object and is measured in. Page 9
Put your answers to Homework Exercise 1 here. Page 10
Forces Homework 2 Non-contact Forces and Friction 1. Name the three non-contact forces you have learned about. 2. Identify which non-contact force is present in the following pictures. (a) (b) (c) 3. What type of magnet is shown in the following picture? 4. What are two ways of making this magnet stronger? 5. Which force slows down an object s movement and is caused by two surfaces rubbing together? 6. What is the main type of energy produced by friction? 7. Friction can be reduced by putting air in between the two surfaces e.g. like a puck on an air hockey table. What is another way friction could be reduced? 8. Friction can be useful when trying to open a jar of jam. Give another example when friction is useful. Page 11
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Put your answers to Homework Exercise 2 here. Page 13
Forces Homework 3 Balanced and Unbalanced Forces 1. What is the name given to forces that are equal in size but opposite in direction? 2. What is the name given to forces that are not balanced? 3. Read the following statements and identify whether the forces are balanced or unbalanced: (i) A car accelerating (speeding up). (ii) A car travelling at constant speed. (iii) A car decelerating (slowing down). (iv) A car stationary. 4. Look at the following diagrams. (a) (b) 20N 20N 20N 10N (c) (d) 20N 20N 40N 40N (i) Identify whether the forces are balanced or unbalanced. (ii) Calculate the unbalanced (total, overall) force. (iii) If the vehicles were stationary when the forces are applied, state whether the vehicle will move left, right or remain stationary. Page 14
Put your answers to Homework Exercise 3 here. Page 15
Forces Homework 4 Levers 1. What is the name of the device which allows us to increase the size of a force? 2. What are the levers called in the following diagrams? (a) (b) (c) The law of the lever states that: The force (F L ) x distance (d L ) on the left side of the see-saw = The force (F R ) x distance (d R ) on the right side of the see-saw 3. Calculate the force on the right side (F R ) to make the seesaw balance; an example is done for you below. Show your working in the same way: F L x d L = F R x d R 5 x 6 = F R x 3 5N F R 30 = F R x 3 F R = 30 / 3 6cm 3cm F R = 10 N (a) (b) 7N F R 6N F R 4cm 2cm 4cm 3cm Page 16
Put your answers to Homework Exercise 4 here. Page 17
Forces Summary 1. A force can: - Change the of an object. - Change the of an object. - Change the of an object. 2. An example of an object s speed being changed by a force is:. 3. An example of an object s direction being changed by a force is:. 4. An example of an object s shape being changed by a force is:. Contact Forces 5. Four contact forces are: 6. A force would be needed to open a bottle of juice. 7. A force would be needed to drag a sledge. Page 18
8. A force would be needed to change the channel on the TV. 9. A force would be needed to unwrap a present. Measuring Force 10. A or can be used to measure force. 11. The unit for force is the ( ). Mass and Weight Mass and weight are different quantities. 12. can be described as the amount of stuff in an object. 13. The unit for mass is the ( ). 14. is the pull of gravity on an object. 15. The unit for weight is the ( ). 16. Weight is a. 17. To convert mass to weight, use the formula: Weight = mass x On Earth g = newtons per kilogram Non-contact Forces 18. Three non-contact forces are: 19. The force of causes objects to accelerate towards the centre of the Earth. Page 19
20. An force will cause charged polythene rods to one another. 21. Only materials which contain will be attracted by a magnet because of the force. Steel is a material which contains iron. The Electromagnet 22. An electromagnet is made from: - an. 23. Electromagnets can be made stronger by: - the number of turns. - the number of batteries. The Force of Friction 24. Friction is a. It down an object s movement. 25. Friction is caused by two rubbing together. 26. Fiction acts in the direction to the object s motion. 27. The main type of energy produced by friction is. 28. Friction can be reduced by putting, or between the two surfaces. 29. Friction can be useful when:. Page 20
Balanced and Unbalanced Forces 30. When forces on an object are they are equal in size but opposite in direction. 31. When forces are not balanced they are described as. 32. Balanced forces cause an object to remain or travel at speed. 33. When forces on an object are the object accelerates or decelerates. The Lever 34. The lever is a device which allows us to the size of a force. Examples of levers are: 35. The law of the lever states that: The force (F L ) x distance (d L ) on the left side of the see-saw = The force (F R ) x distance (d R ) on the right side of the see-saw. Properties of Materials Different materials are chosen for a job because of their properties: 36. Two properties of steel are: Page 21