In an electrically neutral atom the number of protons in a nucleus is equal to the number of?

Abaseball picther can throw a ball at about 90 miles per hour, v = 40 m/s, on solid rock ground. we now put him into space. when he throws the ball, which weighs mb = 0.15 kg moves away from himat the same speed. how long does it take the ball thrown in space to travel the 30 meters to the batter? he weighs mp = 100kg

If we decrease the amount of force and keep all other factors the same what will happen to the amount of work

The height of the empire state building is 318 m if a stone is dropped from the top of the building what is the stones velocity just before it strikes the ground