What is the magnitude of the acceleration of a skydiver who is currently falling at four-fifths his eventual terminal speed?

A500g object falls off a cliff and losers 100 j from its gravitational potential energy store. if the gravitational field strength g=9.8n/kg, how high is the cliff?

Could someone . i have tried to solve myself but my calculation is off

Two point charges are separated by a certain distance. how does the strength of the electric field produced by the first charge, at the position of the second charge, change if the second charge is doubled? a. the field does not change b. the field strength decreases by half. c. the field strength doubles d. the field strength quadruples