Chapter 2 Homework Questions (Motion) 1. 2. 3. 4. 5. Convert 65 km to m. Convert 72 min to seconds. Convert 20 min to hours. Convert 850 sec to hours. Convert 1.7 meters to inches. (1.00 inch = 2.54 cm) 6. Convert 55 km/hr to m/s. 7. Convert 200 m/s to km/hr. 8. Convert 48 km/hr to m/s. 9. Convert 35 km/hr to m/s. 10. Convert 22 miles/hour to m/s (1.61 km = 1.00 mile) 11. Convert 1125 cm2 to m2. 12. What is the difference between scalar and vector quantities? 13. Is speed a vector or scalar quantity? Explain. 14. Is velocity a vector or scalar quantity? Explain. 15. Is an object that is motionless considered to be at a constant or changing speed? Explain. 16. If Mr. West runs the 200 yard dash in 10 seconds, what is his speed? 17. A snowstorm is moving towards Pennsylvania from the Great Lakes which are 500 miles away. The storm should hit in 5 hours. What is the speed of the snow storm? 18. What is the average speed, in km/hr, for a car that travels 22 km in exactly 15 minutes? You must convert units in this problem. 19. Suppose a radio signal travels from earth and through space at a speed of 300,000,000 m/s. How far (in km) into space did the signal travel during the first 20.0 minutes? Remember to convert your minutes to seconds first. 20. What is the average speed of a truck that makes a 285 mile trip in 5.0 hours? Express your answer in miles/hour. 21. A sprinter runs the 200 m dash in 21.4 seconds. What was the sprinter’s speed? 22. If the sprinter were able to maintain that pace, how long (in hours) would it take for him or her to run the 420.0 km between St. Louis and Chicago? 23. What average speed must you drive to make a 400.0 mile trip in 8 hours? In 7 hours? 24. How far away was a lightning strike if thunder is heard 5.00 seconds after seeing the flash? Assume the sound traveled at 350.0 m/s. 25. A bullet leaves a rifle with a speed of 2,360 ft/s. How much time elapses before it strikes a target 1 mile (5,280 ft) away? 26. Is velocity constant for an object falling near the surface of the earth? 27. Is acceleration constant for an object falling near the surface of the earth? 28. What is the difference between average and instantaneous speed? 29. What are the two types of acceleration? (Hint: changes in_____ or ______) 30. Why don’t we feel the speed of the earth as it hurtles through space at incredible speeds? 31. What is the acceleration of a car that moves from rest to 15.0 m/s in 10.0 s? 32. What is the main difference in how Aristotle thought objects fall and how Galileo thought objects fall? Who was correct? 33. Why don’t falling objects accelerate forever in an atmosphere? 34. In a snail race, Lance Snailstrong began to tire and slowed down at a rate of 2 cm/min over the course of 5 minutes. What was his deceleration? 35. A hybrid car can accelerate from rest at a stop light to 50 mi/min in 2 minutes. What is it’s rate of acceleration? 36. A truck slows down from 55 km/hr to 30 km/hr over a period of 4 hours. What is the deceleration? 37. A roller coaster goes from 30 mi/hr to 60 mi/hr in 5 seconds. What is the acceleration? (Hint: express your answer in mi/hr/s) 38. A frozen turkey dropped from a window strikes the ground 2.00 seconds later. How high is the window above the ground? 39. In the previous problem, at what speed did the turkey hit the ground? 40. A cell phone is observed to fall from a bridge, striking the water below 2.50 s later. How high is the bridge? 41. In the previous problem, at what speed did the cell phone hit the water? 42. A car accelerates from 0 to 72 km/s in 8 seconds. What is the car’s acceleration? 43. What is the acceleration of a racer who crosses the finish line at a speed of 20 m/s and stops running 4 seconds later? 44. How long will it take a bicyclist to stop if they are travelling at 6.67 m/s and their brakes provide a deceleration of 1.334 m/s2?