Ken and Joanne are astronauts floating some distance apart in space. They are joined by a safety cord whose ends are tied around their waists. If Ken starts pulling on the cord, will he pull Joanne toward him, or will he pull himself toward Joanne, or will both astronauts move? Explain.

A black aluminum glider floats on a film of air above a level aluminum air track. Aluminum feels essentially no force in a magnetic field, and air resistance is negligible. A strong magnet is attached to the top of the glider, forming a total mass of 240 g. A piece of scrap iron attached to one end stop on the track attracts the magnet with a force of 0.823 N when the iron and the magnet are separated by 2.50 cm. (a) Find the accelerationof the glider at this instant. (b) The scrap iron is now attached to another green glider, forming total mass 120 g. Find the acceleration of each glider when the gliders are simultaneously released at 2.50-cm separation.

A mischievous child ties a June Bug (a large beetle) on to string. The child holds his arm above his head and the bug attached to the string flies around in a horizontal circle. What is the direction of the net force on the bug?

An astronaut on the moon places a package on a scale and finds its weight to be 35 N. (a) What would the weight of the package be on the earth?                      N(b) What is the mass of the package on the moon?                      kg(c) What is the package's mass on earth?                       kg