Imagine for a minute that the moon is held in its orbit about the earth by electrical forces rather than by gravitation. what electrical charges −q on the earth and +q on the moon are necessary to hold the moon in a circular orbit with a period of 27.3 days? the earth-moon distance is 384 000 km and the mass of the moon is 7.35 × 1022 kg.

When you jump from an elevated position you usually bend your knees upon reaching the ground. by doing this, you make the time of the impact about 10 times as great as for a stiff-legged landing. in this way the average force your body experiences is a) less than 1/10 as great. b) more than 1/10 as great. c) about 1/10 as great.d) about 10 times as great.