ASTR120 HOMEWORK # 2 - Due September 17


1) Do #5 in the Thought Questions section in Chapter 2.




2) Do # 13 in the Problem section in Chapter 2.




3) What would be the period of an object in circular orbit at a distance of 1000 km above the surface of the Sun? What would its orbital velocity be in meters/sec?




4) Do #7 in the Thought Questions in Chapter 3.




5) If you are traveling in a car which decelerates from 60 miles/hour to 0 miles/hour in a distance of 20 feet (crash), what force will you feel? Assume that you are decelerated at a constant rate. How much would you weigh if you measured your weight in the direction of deceleration?

Hint: Distance = ${1 \over 2}$ (acceleration) $\times$ (time)2




6) Calculate the gravitational force between a 70 kg person and a 3 kg baby sitting 1 meters away. Compare this to the gravitational force between the baby and the planet Jupiter. Assume that Jupiter is located at closest approach to the Earth.