2. The Man’s Jeopardy

3. Learning Objectives 1.Describe what a force is. 2.Describe how balanced and unbalanced forces are related to an object’s motion. 3.Describe friction and identify the factors that determine the frictional force between 2 objects. 4.Identify the factors that affect the gravitational force between two objects, and describe how they affect this force. 5.Explain why objects accelerate during free fall (by describing how gravity affects falling objects). 6.Apply Newton’s 1 st Law of Motion to real world examples. 7.Apply Newton’s 2 nd Law of Motion to real world examples. 8.Apply Newton’s 3 rd Law of Motion to real world examples. 9.Explain how an object’s momentum is conserved & calculate momentum. 10.State the law of conservation of momentum.

4. RULES 1.There will be round robin play and all questions will be all-play except for the daily doubles. 2.The teams who answers correctly win the point value of the question. 3.If a team answers a daily double incorrectly, then that team will lose the number of points they bid, and any other team can “ring in” by raising their hand and answer at that point. 4.There are two daily doubles available. Let’s play

5. 100 200 300 400 500 Final Jeopardy 100 200 300 400 500 Forces & Friction Gravity Newton’s Laws 1&2 Newton’s 3 rd Law & Momentum

6. Forces & Friction for 100 Which of the following is NOT an example of exerting a force: pushing a button, punching the PSU mascot, running to school? What effect do unbalanced forces have on an object’s motion? Running to School (not exerting a force) Unbalanced forces change an object’s motion.

7. Forces & Friction for 200 An object is falling toward the Earth at 9.3 m/s/s. Why is the object not falling at 9.8 m/s/s? What type of force resists the object’s motion in the opposite direction? Air Resistance Friction

8. Forces & Friction for 300 What force typically causes momentum to seem like it was NOT conserved? Example- the collision of two hockey players. Friction

9. Forces & Friction for 400 Give an example of how decreasing friction is helpful. Oiling a machine or bike, waxing a snowboard, using a cart with wheels to move an object

10. Forces & Friction for 500 Using the diagram below, what direction is the net force on the object? What is the net force? How could you balance the forces on the object? Down, 50 N, Increase the upward force by 50 N 150 N 200 N

11. Gravity for 100 The force that acts on all objects on Earth and is the only force acting on an object in free-fall is ___________. Gravity

12. Gravity for 200 How can the gravitational attraction between 2 objects be decreased? Lower the mass and spread the objects further apart.

13. Gravity for 300 Suppose a planet with a mass of 100.5 x 10 24 kg was discovered. Based upon the data above, what is a possible value for the gravitational pull of this new planet? Any value from 1.1 to 2.3 would be correct. The best values would be between 1.1 and 1.5. Planetary BodyMass (x 10 24 kg)Gravitational Pull (relative to Earth) Pluto0.00130.1 Earth’s Moon0.070.2 Mars0.640.4 Earth5.981.0 Jupiter19002.4 The Sun1,989,0007.1

14. Gravity for 400 Bob and Joe believe that heavier objects fall faster. They design an experiment to test out their prediction. What is their hypothesis? What is the independent or manipulated variable? What is the dependent variable? What are 2 variables that Bob and Joe should try to keep constant? Hypothesis- Heavier objects fall faster. Ind. Variable- The weight or mass of the objects Dep. Variable- Time it takes for the object to hit the ground OR acceleration Constants- Height of the drop, air/wind resistance (if possible), same timer or timekeeper, etc.

15. Gravity DAILY DOUBLE! Three satellites are orbiting the Earth. The distance from Earth is 6,000 km for Satellite A; 10,000 km for Satellite B; and 35,800 km for Satellite C. Which one would Earth have the greatest attraction for? Explain why. Satellite A because it’s the closest.

16. Newton’s Laws 1 & 2 for 100 The ability of an object to resist a change in motion is called ___________. Inertia

17. Newton’s Laws 1 & 2 for 200 What types of objects have the greatest inertia? What do objects in motion tend to do? What do objects at rest tend to do? Heavier objects Objects in motion tend to stay in motion Objects at rest tend to stay at rest

18. Newton’s Laws 1 & 2 for 300 An object accelerates at 4 meters per second 2 for a force of 20 N. How much force is needed for an acceleration of 2 m/s/s for the same object? If the amount of force on a heavy object is the same as the amount of force on a lighter object, then which object will have the lower acceleration? Half the acceleration for a constant mass = half the force, so 10 N The heavier object will have the lower acceleration.

19. Newton’s Laws 1 & 2 for 400 A 100 kg person is skydiving. What is the force of gravity (or weight) acting on the skydiver? F = m x a F = 100 kg x 9.8 m/s/s F = 980 N

20. Newton’s Laws 1 & 2 DAILY DOUBLE!!! Give two real world examples of Newton’s 1 st Law (you may do this verbally instead of writing it down). A car stops and your body moves forward, a car takes off and your body moves backward, etc.

21. Newton’s 3 rd Law & Momentum for 100 According to Newton’s 3 rd Law, for every action there is an _________ and ________ reaction. For every action there is an equal and opposite reaction.

22. Newton’s 3 rd Law & Momentum for 200 What are the action-reaction forces when a carpenter hammers a nail? Action = hammer striking the nail Reaction = nail pushes back on the hammer

23. Newton’s 3 rd Law & Momentum for 300 How is momentum calculated? True or False. Change the underlined word to make it true. The momentum of an object is in the OPPOSITE direction of that object’s velocity. Momentum = mass x velocity False, momentum is in the SAME direction as the object’s velocity.

24. Newton’s 3 rd Law & Momentum for 400 If the total momentum after a collision is 10 kg x m/s, then what was the total momentum before the collision? Explain how you know. 10 kg x m/s because momentum is conserved (remains the same and is not lost, only transferred)

25. Newton’s 3 rd Law & Momentum for 500 How can an object’s momentum increase? How does an object’s mass affect its momentum? Moving faster or higher velocity Greater the mass, the higher the momentum

26. Force Diagram Draw a force diagram for a person pushing a large oven up a ramp toward the left. Label all of the forces acting on the box using arrows of the correct length.