Which kind of force do you exert on an object when you pull it toward you?

How would doubling the made of an object change the objects potential energy

Which of the following is not am example of a polymer? protein nylon kevlar concreta

Alead ball is dropped into a lake from a diving board 5m above the water . it hits the water with a certain velocity and then sink with constant velocity in bottom . it reaches the bottom 5 second after it is dropped if g= 10m/s2 . find depth of the lake and average velocity of the ball ?