A 45 kg student is riding on a 7kg skateboard with a velocity of +4 m/s. The student jumps off the skateboard with a velocity of 1 m/s. Find the velocity of the skateboard after the student jumped off.

Consider two less-than-desirable options. in the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. in the second option you are driving 30 mph and crash head-on into a stationary brick wall. in neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. which of these two situations would result in the greatest impact force?

The electric field inside a cell membrane is 8.0mn/c. what's the force on a singly charged ion in this field?

Which of the following characteristics is fixed, or definite, for all states of matter?