physics multiple choice

A person stood at rest on the floor. the reaction force of the gravity force on him was a. the force of him pulling the earth up b. the force of the earth pushing him up c. the force of him pushing the earth up d. the force of the earth pulling him down

a. the force of him pulling the earth up

In the absence of air friction, an object dropped near the surface of the Earth experiences a constant acceleration of about 9.8 m/s during each second. this means that the a. object falls 9.8 meters during each second b. speed of the object as it falls is 9.8 m/s c. speed of the object increases 9.8 m/s during each second d. rate of change of the displacement with respect to time for the object equals 9.8 m/s^2

c. speed of the object increases 9.8 m/s during each second

Which of the following statements is true for a ball thrown vertically upward? a. the ball has a negative acceleration on the way up and a positive acceleration on the way down b. the ball has a zero acceleration at the very peak of its flight c. the ball has a constant acceleration through out its flight d. the ball has a positive acceleration on the way up and a negative acceleration on the way down

c. the ball has a constant acceleration through out its flight