# Physics Mid-Term Exam  revision  8/19/14DirectionsIt is i

Physics Mid-Term Exam revision 8/19/14Directions:It is important that you provide answers in your own words. Please focus only on information from the text/eBookto create your own solutions. Please do not use direct information froman outside source (especially copying and pasting from an “answer” website).Use of direct information from an outside source is against schoolpolicy. Allanswers will be checked for plagiarism. Instances of plagiarismcanresult in probation or possible dismissal from the school.Grading:Please be sure to follow all guidelines (number ofsentences/showing all calculations) and to provide the correct metric units ofmeasure. All questions are 5 points (1point for sentence number /correct units).1. Makayla is talking to Mia about the whether weever landed on the Moon. Mia says,” Ihave a theory about that.” Using 3 – 4complete sentences, what is wrong with Mia’s use of the term “theory” in thisinstance?2. Choose ONE of the scenarios below, thendesign an experiment and describe a procedure to enable you to make an estimateof the average speed. Your description should include the materialsyou would need and how you would use them to collect the data you need.a. A baseball thrown from outfield to home plateb. The windc. A raindropd. A hand moving back and forth as fast as possiblee. The tip of a swinging baseball batf. An eye blinkingg. A whisker growing3. There are many familiar situations in whichthenet force on a body is zero and yet the body moves with a constantvelocity. One example is describedbelow:A car traveling atconstant speed on a straight road has the force of the road on the tires justbalanced by the force of air friction. If the gas pedal is depressed further, the tires will push against theroad harder and the road will push against the tires harder; so the car willaccelerate forward – until the air friction builds up enough to balance thegreater drive force. Giveanother example of a body moving with constant velocity under balancedforces. Specify the cause of each forceon the body and explain how these forces could be changed to affects the body’motion.4. If a person weighs 500 N on Earth, what wouldshe weigh on Jupiter, where the acceleration due to gravity is 26 m/s2? Show all work leading to your answer.5. If a freely falling rock were equipped with aspeedometer, by how much would its speed readings increase with each second IFit were on a planet where g = 20 m/s2? Show all work leading to your answer.6. Cleo and Clare are looking from their balcony toa swimming pool below that is located 15 m horizontally from the bottom oftheir building. They estimate thebalcony is 45 m high and wonder how fast they would have to jump horizontallyto succeed in reaching the pool. Whatcalculations would you show to help them determine the answer? Evaluate the practicality of their being ableto succeed at jumping into the pool.7. An airplane has a gun that fires bulletsstraight ahead at the speed of 600 miles per hour when tested on the groundwhile the plane is stationary. The planetakes off and flies east at 600 miles per hour. Explain whether each of thefollowing is possible for the pilot to measure:a. When fired directly ahead the bullets moveeastward at a speed of 1200 miles per hourb. When fired in the opposite direction (by turningthe gun westward, but not the plane), the bullets drop vertically downwardc. If fired vertically downward (by turning the gundownward, but not the plane), the bullets move eastward at 600 miles per hourwhile they fall.8. A falling 50-kg skydiver experiences an upwardacceleration of 6.2 m/s2 when she opens her parachute. Show (by calculation) how much drag force isproduced by the parachute.9. In three scenarios a truck is towing a boat on atrailer. Using 3 – 4 complete sentences indicatewhich scenario(s) (if any) is the force of the truck on the trailer greaterthan the force of the trailer on the truck: ScenarioA: masstruck = 1000 kg, massboatand trailer = 500 kg; velocity = 20 m/s ScenarioB: masstruck = 800 kg, massboatand trailer = 800 kg; velocity = 20 m/s ScenarioC: masstruck = 500 kg, massboatand trailer = 1000 kg; velocity = 15 m/s10. A bug and the windshield of a fast-moving carcollide. Indicate whether each of thefollowing statements is True or False (1 point each)a. The forces of impact on the bug and on the carare the same magnitude.b. The impulses on the bug and non the car are thesame magnitudec. The changes in speed of the bug and of the carare the same magnitude.d. The changes in momentum of the bug and of thecar are the same magnitude.e. The accelerations of the bug and the car are thesame magnitude.11. Betty and Bianca weigh the same amount and theyclimb a flight of stairs. Betty climbsthe stairs in 30 seconds. Bianca climbsthe stairs in 40 seconds. In terms offorce, work and power, evaluate which of the three quantities (if any) isgreater for Betty or for Bianca? Justifyyour answers using 3 – 4 complete sentences.12. Leon’s bicycle wheels have a circumference of 2m. What is his linear speed when thewheels rotate at 1 revolution per second? Show all work leading to your answer.13. This graphic shows a scene from atrapeze act. Write 3 – 4 complete sentences to describe the physics pictured in thisscene. Use the terms inertia, centripetal acceleration, force,gravity, and velocity in your description.14. Using 6400 km as the radius of Earth, calculate howhigh above Earth’s surface you would have to be in order to weigh 1/16thof your current weight. Show all workleading to your answer OR describe your solution using 3 -4 complete sentences.15. The sun’s mass is about 2.7 x 107times greater than the moon’s mass. Thesun is about 400 times farther from Earth than the moon. How does the gravitational force exerted onEarth by the sun compare with the gravitational force exerted on Earth by themoon?16. At a particular point, a satellite in anelliptical orbit has a gravitational potential energy of 7000 MJ with respectto Earth’s surface and a kinetic energy of 4000 MJ. At another point in its orbit, the satellite’spotential energy is 2000 MJ. What is itskinetic energy at that point? Show allcalculations leading to your answer.17. If a stationary cart is struck head-on by a cartwith twice mass of the stationary one and a velocity of 5 m/s, what will be thenew velocity of the stationary cart if the collision is inelastic? Show allcalculations leading to an answer.18. A 2.0-gram bullet is shot into a treestump. It enters at a speed of 3.00 x 104cm/sand comes to rest after having penetrated 0.05 m in to the stump. What was the average force during theimpact? Show all calculations leading toan answer.19. Can you get younger by traveling at speeds nearthe speed of light? Explain using 3 ormore complete sentences.20. A beam of light and a baseball are both affectedby gravity. Why is the path of thebaseball very different than the path of the light beam? Use 3 – 4 completesentences in your explanation.