A 40 kg ice skater traveling at 0.5 m/s to
the east collides with
a 35 kg ice skater
traveling at 1.5 m/s to
the west. The two
skaters travel
together after the
collision. How fast do
they travel and in
which direction?

The star betelgeuse is about 600 light-years away. if it explodes tonight, a. we'll know because debris from the explosion will rain down on us from space.b. we'll know it immediately because it will be brighter than the full moon in the sky.c. we won't know about it until 600 years from now.d. none of the above.

Most of the volume of an atom is occupied by the

Suppose that 27 j of work is needed to stretch a spring from its natural length of 6 m to a length of 9 m. (a) how much work is needed to stretch the spring from 12 m to 14 m? j (b) how far beyond its natural length will a force of 78 n keep the spring stretched?