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Problems from chapter 2 (p.26):
26. Calculate the average speed (in m/s) of a cheetah that runs 140 m in 5 seconds.
27. (A) Calculate the average speed (in km/h) of Charlie, who runs to the store which is 4 kilometers away in 30 minutes. (B) Calculate the distance (in km) which Charlie runs if he maintains the same average speed for 1 hour.
28. What is the acceleration of a car (in km/h.s) that can go from rest to 100 km/h in 10 s.
29. Calculate the instantaneous speed (in m/s) at the 10- second mark for a car that accelerates at 2m/s^2 from a position of rest.
33. An object falls freely from rest. Find its instantaneous speed and the distance it has fallen after 8 seconds
42. If humans originated in Africa and migrated to other parts of the world, some time would be required for this to occur. At the modest rate of a mere 1 kilometer per year, how many centuries would it take for humans to reach China, some 10,000 kilometers away?
47. If you throw a ball straight up at a speed of 10 m/s, how long will it take to reach zero speed? How long will it take to return to its starting point? How fast will it be going when it returns to its starting point?
Chapter 3 (p.41)
19. (A) Calculate the resultant speed of an airplane that normally flies at 200 km/h if it encounters a 50 km/h tailwind. (B) If it encounters a 50 km/h headwind.
20. Calculate the resultant of a 100 km/h velocity north and a 75 km/h south.
21. What is the magnitude of the resultant of a pair of 100 km/h velocity vectors that are at right angles to each other?
25. What are the horizontal and vertical components of a 10-unit vector which is oriented 37 degrees above the horizontal?
29. What are the maximum and minimum possible resultants of two vectors with magnitudes of 4 and 5 units?
31. The speed of falling rain is the same 10 m above the ground as it is just before it hits the ground. What does this tell you about whether or not the rain encounters air resistance?
32. Rain falling vertically will make vertical streaks on a car's side window. However, if the car is moving, the streaks are slanted. If the streaks from a vertically falling rain make 45 degree streaks, how fast is the car moving compared with the speed of the falling rain?
Chapter 4 (p.56)
21. If a woman has a mass of 50 kg, calculate her weight in newtons.
22. Calculate in newtons the weight of a 2000 kg elephant.