Answers to even questions in Chapter 7.   Notify me of any disagreement.

2.  The wheel travels 2.2 m, 120 m and 770 m respectively.

4.  The Earth's angular speed is 1.99*10(-7) rad/sec, or ).986 degrees/day.

6.  The angular acceleration of the tire is 41 rad/s^2.

8.  a) The drill's angular acceleration is 822 rad/s^2.
    b) The angle rotated through in the first 3.20 s is 4.21*10^3 rad.

10. The tub turns through 50 revolutions during the 20.0-s interval.

12. a) The angular acceleration of the mass is 0.14 rad/s^2.
    b) The angular speed after 1.00 min is 8.4 rad/s.

14. The wheels turn through a total of 36.5 revolutions during the acceleration.

16. a) The centripetal acceleration at the equator is 3.37*10(-2) m/s^2.
    b) The centripetal acceleration at the North Pole is 0 m/s^2.

18. The acceleration of the stone in the tire is 2.4*10^3 m/s^2.

20. a) The speed of the race car is 14.14 m/s.
    b) The distance travelled is 200 m.
    c) The elapsed time is 28.3 s.

22. The car can go up to a speed of 12 m/s without skidding.

24. a) The minimum radius of the circular path is 146 m.
    b) The centripetal force on the pilot is 5.5 kN.

26. a) The tension in the string is 9.8 N.
    b) The force causing the centripetal acceleration is 9.8 N.
    c) The speed of the puck is 6.3 m/s.

28. a) The centripetal acceleration of the child is 1.58 m/s^2.
    b) The seat exerts a force of 455 N at the lowest point.
    c) The seat exerts a force of 329 N at the highest point.
    d) The seat exerts a force of 397 N at the midway point.

30. The minimum speed of the pail at the top must be 3.13 m/s.

32. a) The force exerted on the Moon by the Sun is 4.39*10^(20) N.
    b) The force exerted on the Moon by the Earth is 1.99*10^(20) N.
    c) The force exerted on the Earth by the Sun is 3.55*10^(22) N.

34. The forces exerted by the Earth and the Sun cancel at 2.6^10^8 m from earth.

36. a) The satellite's altitude above the Earth's surface is 9.58*10^3 km.
    b) The orbital period of the satellite is 5.55 hr.

38. a) The satellite's acceleration is 1.62 m/s^2.
    b) The satellite's speed is 1.68 km/s.
    c) The satellite's period is 108 min.

40. a) Escape speed from the Moon is 2.38 km/s.
    b) Escape speed from Mercury is 4.18 km/s.
    c) Escape speed from Jupiter is 60.2 km/s.
 
42. a) The angle the line makes with the original direction is 156 degrees.
    b) The angular speed at t=2.00 s is 6.00 rad/s.

44. a) The tangential speed of the ball is 2.51 m/s.
    b) The centripetal acceleration of the ball is 7.90 m/s^2.
    c) The maximum permissible tangential speed is 4.00 m/s

46. a) The angular speed of the disk is 126 rad/s.
    b) The linear speed 2.00 cm from the center is 2.51 m/s.
    c) The centripetal acceleration on the rim is 947 m/s^2.
    d) The total distance travelled at the rim in 2.00 s is 15.1 m.

48. a) The radius for a geosyncronous orbit is 4.23*10^4 km.
    b) Geosyncronous satellites are 2.23*10^4 miles above the earth's surface.

50. a) The tension in the pendulum cable at its lowest point is 8.42 N.
    b) The maximum angle the cable makes with the vertical is 64.8 degrees.
    c) At the highest point, the tension in the cable is 1.67 N.

52. a) Weight_Equator=m*g-m*a_c.
    b) Apparent weights are 735 N (Pole) and 732.5 N (Equator).

54. a) Tension at beginning of motion is 0 N.
    b) Tension 1.5 m above bottom is 1.3 kN.
    c) Tension at bottom is 2.1 kN.

56. See solution for details. (Hint: calculate where normal force becomes zero.)

58. Planet Y has turned through 1.30 revolutions after 5 years.

60. The speed of the rock on entering the Earth's atmosphere is 11.8 km/s.

62. The minimum required compression of the spring is 0.75 m.

64. a) The maximum value of v_0 is sqrt(g(R-2h/3)).
    b) The maximum height, h', for the roller-coaster is R/2 + 2h/3.