Physics 1

The graph below is a plot of displacement versus time of a mass oscillating on a spring.

73. At which point on the graph is the acceleration of the mass zero?
a. A c. C
b. B d. D

74. At which point on the graph is the velocity of the mass zero?
a. A c. C
b. B d. D

75. At which point on the graph is the net force on the mass at a maximum?
a. A c. C
b. B d. D

76. On the graph, mark the amplitude.

77. A child swings back and forth on a playground swing. If the child stands rather than sits, the time for a to-and-fro swing is __________. Explain.

78. An astronaut lands on an unknown planet and must determine the value of the gravitational acceleration g using a simple pendulum at the end of an arm that is 0.500 m long. The astronaut counts exactly 47 full swings in 1.00 min. What is the value of g?

79. The frequency of the second hand on a clock is __________. 80. A simple pendulum has a string that is 20.0 cm long with a 100.0-g mass suspended from the end. Pulling the mass 2.0 cm to one side and releasing it starts the pendulum in motion.
a. What is the amplitude of this pendulum?
b. What is the period of this pendulum?
c. If the string is lengthened to 50.0 cm, what happens to the period? (Be very specific.)
d. If the mass is increased to 500.0 g, what happens to the period?
e. If the mass is pulled 4.5 cm to one side and released, what happens to the period?

81. Part a of the figure below shows a pulse traveling at a speed of 1.0 m/s in a coil spring to which a second spring is