Unit 6 Study Guide. 4. Does the speedometer of a car read average speed or instantaneous speed? How do you know?

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1 Unit 6 Study Guide PART 1: SPEED/ACCELERATION CONCEPTS 1. What is speed? 2. What is the difference between speed and velocity? 3. What is acceleration? 4. Does the speedometer of a car read average speed or instantaneous speed? How do you know? 5. Which two controls on a car cause a change in speed? 6. What is the acceleration of a car that travels in a straight line at a constant speed? 7. If we were to graph the above acceleration, what would the graph look like? 8. What is the acceleration of a car that is slowing down for a red light? 9. If we were to graph the above acceleration, what would the graph look like? 10. Explain to me how a car can be accelerating if it is moving at a constant speed (notice I did not say "velocity"). 11. How can you tell the difference between a speed graph and an acceleration graph? (Hint: what is different about the axis for the graphs?) PART 2: FORCE CONCEPTS 1. The statement to every reaction there is an equal and opposite reaction is. law of conservation of momentum c. Newton s second law of motion b. Newton s first law of motion d. Newton s third law of motion 2. The relationship among mass, force, and acceleration is explained by. a. Newton s first law of motion c. Newton s third law of motion b. Newton s second law of motion d. the conservation of momentum 3. When a car turns to the left, and your body feels like it is being thrown to the right, is explained by. a. Newton s first law of motion c. Newton s third law of motion b. Newton s second law of motion d. the conservation of momentum

2 4. A feather will fall through the air more slowly than a brick because of. a. gravity c. terminal velocity b. air resistance d. momentum 5. In the absence of air, a penny and a feather dropped from the same height will. a. fall at different rates c. fall at the same rates b. float d. not have momentum 6. The amount of gravitational force between objects depends on their. a. frictional forces c. inertia b. speed and direction d. masses and the distances between them 7. If a 300-N action force is exerted to the right, the reaction force will be. a. 300 N to the right c. 300 N to the left b. 600 N to the right d. 600 N to the left 8. When a force is exerted on an object, an equal and opposite force is exerted by the object. These forces are referred to as. a. centripetal forces c. gravitational forces b. friction forces d. action-reaction forces 9. Acceleration due to gravity is. a. 98 m/s2 c. 9.8 m/s b. 9.8 m/s2 d m/s 10. A real car moving at 10 km/h has more momentum than a toy car moving at the same rate because. a. its mass is greater c. it moves faster b. its mass is less d. of friction 11. What are Newton s 3 laws of motion, in order? For each of the following situations, tell me if we are dealing with Newton s 1 st, 2 nd, or 3 rd law. When you jump out of a boat, the boat floats backwards after you jump. A magical pulls a tablecloth out from under dishes on the table without them falling off the table. A person s body is thrown towards the right as a car rounds a curve left on the highway. A picture is hanging on a wall and does not move. Pushing a small child on a swing is larger than pushing a large adult. A soccer ball accelerates more than a blowing ball when thrown with the same force. A person not wearing a seatbelt flies through a car window when the car crashes into something. 13. What is a force? 14. What are our units for force? 15. What is a Newton? 16. What is weight?

3 17. What is our equation for weight? 18. Does weight or mass change if we move to another planet? 19. What is friction? PART 3: PRACTICE Speed, Velocity, Acceleration, Force, Weight Complete the following problems. Show the formula, all work and include units in your answer! 1. A roller coaster car rapidly picks up speed as it rolls down a slope. As it starts down the slope, its speed is 4 m/s. But 3 seconds later, at the bottom of the slope, its speed is 22 m/s. What is its average acceleration? 2. Find the average speed of a walk to school and back if you took 12 minutes to walk there and 18 minutes to walk back. The school is 1.5 miles from home. 3. A ball rolling down a hill accelerates from 40.0 m/min to 60.0 m/min in a time period of 3.0 minutes. What is the ball s acceleration? 4. A meteorite changed speed from 1.0 km/s to 0 km/s in 0.03 seconds when it crashed into my car. Not cool. If that meteorite has a mass of 50kg, what is the force of the meteorite on my car? 5. In drag racing, acceleration is more important than speed, and therefore drag racers are designed to provide high accelerations. Suppose a drag racer has a mass of 1250 kg and accelerates at a constant rate of 16.5 m/s 2. How large is the unbalanced force acting on the racer? 6. The longest distance in a field and track event is 10 km run. The record holder for the women s 10 km run is Wang Junxia of China. Assuming that Wang ran a distance of 10.0 km with an average speed of m/s, what was her time?

4 7. A house is lifted from its foundations onto a truck for relocation. The unbalanced force lifting the house is 2850 N. This force causes the house to move from rest to an upward speed of 0.15 m/s in 5.0 s. What is the mass of the house? 8. The massive Imperial walkers used to assault the rebel base on Hoth. The walkers, starting from rest, can reach a final velocity off 17 m/s. If each step requires 63,250 N of force, and the mass of the AT-AT is 145,304 kilograms, how long did each step take (in seconds)? 9. The fastest crossing of the Atlantic Ocean by an ocean liner was made on July 7, The ship, the S.S. United States, traveled 4727 km east by northeast in 3 days, 10 hours, and 30 minutes. Assume that the ship had traveled the same speed, but directly east. What would the velocity of the S.S. United States be in kilometers per HOUR. 10. The elevators in the Landmark Tower in Japan, are among the fastest in the world. They accelerate upward at m/s 2 for 4.00 sec to reach their final speed. If these elevators start at rest, what is their final speed? 11. The little Ewoks on Endor fought a great battle and helped shut down the shield generator during the rebellion assault on the Death Star. An ewok warrior can throw a 1.5 kg spear at a rate of 5 m/s2. With what force can the warrior use the spear? 12. If a person has a mass of 65Kg, what is his weight on Earth? 13. A person has a mass of 45kg on Earth. What is its mass on the mars, knowing that mars has 1/3 the gravity of Earth.

5 PART 4: Graphing! Use the graph with the rubber ducky to answer the following questions. 1. Is this a speed or an acceleration graph? How can you tell? 2. What is the displacement of the rubber ducky at point E? 3. Explain to me what is happening on each of the following lines: a. From point O to A b. From point A to B c. From point B to C d. From point C to D e. From point D to E f. From point E to F 4. What is the velocity of the line from point D to point E? Use the graph with the school bus to answer the following questions. 5. Is this a speed or an acceleration graph? How can you tell? 6. What is the speed of the school bus at point E? 7. Explain to me what is happening on each of the following lines: a. From point O to A b. From point A to B c. From point B to C d. From point C to D e. From point D to E f. From point E to F 8. What is the acceleration of the line from point D to point E?

6 PART 5: HONORS ONLY Vectors: 1. What is the difference between a scalar and a vector? 2. What is a vector showing? 3. 2 puppies are playing. One run 1.5 meters, North, towards the other, and then for some reason breaks East and runs 5 meters away. Draw me the vectors (head to toe) and calculate the resultant vectors distance. 4. Iron man is one crazy super hero. I saw him flying directly towards a building for 220 meters in 1.8 seconds, keeping 1 meter off the ground the whole time. Once he reached a distance of 2 meters from the building, he hit some new thrusters and traveled directly upward to the top of the building 600 meters away, maintaining that 2 meter distance from the building for the entire 4.6 second trip. Draw me the vectors (head to toe), calculate the vectors velocity, and calculate the resultant vectors velocity. Momentum: 5. If a bear has a mass of 220kg and has a momentum of 32kg*m/s, what is the sleep of the moving bear? 6. If a football is thrown and and accelerates 24 m/s 2 in a 15 meter pass, what is the momentum of the football assuming that the ball is thrown with a force of 4N and the pass took 3 seconds to travel the 15 meters? Free Body Diagrams: 7. Draw the forces acting on the box. Assume gravity is 18.6 newtons, and that the table is providing a normal force. Indicate a force pushing the box to the left at 8 newtons, while the table displays a frictional force of 3 newtons. a. Will the box move? b. If yes, which direction will the box move? c. If yes, what is the force that the box will move? 8. Draw the forces acting on the box. Assume gravity is 22 newtons, and that the table is providing a normal force. Indicate a force pushing the box to the left at 7 newtons, while the table displays a frictional force of 17 newtons. a. Will the box move? b. If yes, which direction will the box move? c. If yes, what is the force that the box will move?