On earth a rock is dropped and falls 4.9 meters just before it hits the ground. how much time did the rock take to fall this distance

You watch as a firecracker rises high and explodes in an enormous blossom of light, breaking up into many pieces. Which statement (s) accurately describe the conditions immediately before and after the firecracker explodes: I.

A mysterious rocket-propelled object of mass 45.0 kg is initially at rest in the middle of the horizontal, friction-less surface of an ice covered lake. Then a force directed east and with magnitude F (t) = (16.8 N/s) t is applied.

What is the potential energy of a 150 kg diver standing on a diving board that is 10 m high?

Which of the following statements about rest and physical activity is NOT true? a. You should rest as little as possible because it interferes with training. b. You should allow muscle groups a chance to rest between workouts. c.

How much work must be done on a 5-kg sled to increase its speed from 10 m/s to 15 m/s? A. 25 B. 312.5 J C. 562.5 J D. 5

When a surface vibrates, air is forced to move, creating a sound wave. What kind of force is exerted by the moving surface on the air?

An 800-N billboard worker stands on a 4.0-m scaffold supported by vertical ropes at each end. If the scaffold weighs 500 N and the worker stands 1.0 m from one end, what is the tension in the rope nearest the worker?

When would you use a compound microscope?

What does a Battery and a human have in common?

Why is it better to search new a cliff for a fossil then near a volcano?