Forces Review

1. Forces Review • Which of the following are all different types of forces? • Tension, Centripetal, Inertia • Weight, Normal, Air Resistance • Electromagnetic, acceleration, Gravitational • Friction, Centrifugal, Thrust

2. 2. The units kg*m/s2 is the same as… • Speed • Acceleration • Energy • Force

3. 3. What do we mean by Net Force? • The product of all the Forces acting on an object. • The quotient of all the Forces acting on an object. • The sum of all of the Forces acting on an object. • The absolute value of all the Forces acting on an object

4. 4. A 10 N Force pushes on a box east, a 25 N Force pushes on a box West, and third Force that is 2 N pushes on a box East. What is the Net Force? • 13 N West • 15 N West • 17 N East • 37 N West

5. 5. A 10 N Force pushes on a box east, a 25 N Force pushes on a box West, and third Force that is 2 N pushes on a box East. What Force do you need to add for the Forces to be in equilibrium (balanced) • 13 N West • 13 N East • 37 N East • 17 N West

6. 6. Which of the following free body diagrams represents a hovercraft traveling at a constant speed of 50 m/s? b. a. d c. FN FN FN FAR FAR FAR FAP FAR FAP FAP Fg Fg Fg

7. 7. A 35 kg dog on a leash is struggling to get free. After pushing and pulling for a while with an ongoing force of 500 N, the dog breaks free. How fast will the dog accelerate once he breaks the leash? • 14.2 m/s2 • 1.42 m/s2 • 1.75x104 m/s2 • 0.07 m/s2

8. 8. A 35 kg dog on a leash is struggling to get free. After pushing and pulling for a while with an ongoing force of 500 N, the dog breaks free. Before the dog breaks free, how much Force was the leash putting on the dog? • 14.2N • 500 N • 0.07 N • 0 N

9. 9. A very large man has a mass of 200 kg. What is this man’s weight on earth? ag=9.8m/s2 • 200 N • 1960 N • 200 lbs • 20.4 N

10. 10. What is the Gravitational Force (Fg) or weight of a 55 kg person on Mars if ag=3.47m/s2? • 19.085 N • 191 N • 15.85 lbs • 1.985 N

11. 11. A book is at rest on a table. The force exerted on the book by the table is equal to the book’s a. density b. weight c. volume d. mass

12. 12. A piano is falling from the sky with a constant velocity. The Net Force is ? a.pointing upward b. balanced c. Increasing d. pointing downward

13. Ff 6.3N Fap 37 N 11.5kg 13.The figure below shows a block that is being pulled along the floor. According to the figure, what is the acceleration of the block? • 2.67m/s2 • 0.547 m/s2 • 3.21 m/s2 • 30.7 m/s2

14. 14. A soccer player head butts a .7 kg ball with a force of 25 N. What is the force of the ball on the player’s head? • 35.7 m/s2 • 25 N • 17.5 N • .7 N

15. 1 2 15. A student in a lab experiment jumps upward off a common bathroom scale as the lab partner records the scale reading. • What does the lab partner observe during the instant the student pushes off? a. The scale reading will remain unchanged during the entire time the student is in contact with the scale. b. The scale reading will increase during the entire time the student is in contact with the scale. c. The scale reading will decrease momentarily then will increase as the student is moving upward from the scale. d. The scale reading will increase momentarily then will decrease as the student is moving upward from the scale.

16. 16. An African elephant can reach heights of 13 feet and possess a mass of as much as 6000 kg. Determine the weight of an African elephant in Newtons. • 58800 N • 6000 N • 78,000 N • 612 N

17. 17. Captain John Stapp of the U.S. Air Force tested the human limits of acceleration by riding on a rocket sled of his own design. His rocket sled, known as the Gee Whiz, had a mass of about 82 kg. What net force would be required to accelerate the Gee Whiz and 82-kg Stapp at 450 m/s2 (the highest acceleration tested by Stapp)? a. 804 N b. 3.7x104 N c. 3.6x105 N d. 7.2x105 N

18. 18. Ethan is dragging a bag of grass from the garage to the street on the evening before garbage pick-up day. The diagram at the right is a free-body diagram. It uses arrows to represent the forces acting upon the bag. Each force is labeled according to type. The magnitude of the force is represented by the size of the arrow. Use the free body diagram to determine the net force acting upon the bag. The values of the individual forces are. a. 166.9 N to the right b. 121 N north, 34.5 N to the left c. 20.3 N to the left, 54.8 N south d. 34.5 N to the right Fn Fgrav = Fnorm = 60.5 N Fapp = 40.2 N Ffrict = 5.7 N. Ff FT Fg

19. 19. Inertia is… • Newton’s 2nd Law • The tendency for an object to resist its change in motion. • a Force • an object in equilibrium.

20. 20. Alejandra is attempting to drag her 32.6-kg Golden Retriever across the wooden floor by applying a horizontal force of 420 N. The frictional force is 64N. What is the acceleration? • 10.9 m/s2 • 15 m/s2 • 12.9 m/s2 • 1.96 m/s2

21. 21. A ball is falling towards the ground from 10,000 m in the air. What is the acceleration of the ball? Neglect Air Resistance • 9.8 m/s2 • 15 m/s2 • 12.9 m/s2 • 1.96 m/s2

22. 22. An aileron ______ a plane or glider • lifts • rolls • yaws • stops

23. 23. In order to yaw a plane to the right, turn the rudder to the _____ • left • left then right • right • left then right

24. 24. Which of the following is not a type of plane rotation • pitch • yaw • roll • wash

25. 25. If a glider pitches up, what part of the plane should you add mass to? • front • back • left wing • right wing

26. 26. What must be the Lift Force on the Glider if it has a mass of 2 kg and descends at a constant velocity? • 2N • 2kg • 20N • 20kg

27. 27. Find the acceleration of a 3 kg glider being launched from a rubber band if the glider is catapulted with 27 N? • 30m/s • 9m/s2 • 81Nkg • 9.8m/s2