Questions from Modern Physics

Q: An astronaut’s pack weighs 17.5 N when she is on

An astronaut’s pack weighs 17.5 N when she is on the earth but only 3.24 N when she is at the surface of a moon. (a) What is the acceleration due to gravity on this moon? (b) What is the mass of the p...

Q: Superman throws a 2400-N boulder at an adversary. What

Superman throws a 2400-N boulder at an adversary. What horizontal force must Superman apply to the boulder to give it a horizontal acceleration of 12.0 m/s2?

Q: You throw a baseball straight upward with speed v0. When the

You throw a baseball straight upward with speed v0. When the ball returns to the point from where you threw it, how does its speed compare to v0 (a) in the absence of air resistance and (b) in the pre...

Q: (a) An ordinary flea has a mass of 210 mg

(a) An ordinary flea has a mass of 210 mg. How many newtons does it weigh? (b) The mass of a typical froghopper is 12.3 mg. How many newtons does it weigh? (c) A house cat typically weighs 45 N. How m...

Q: At the surface of Jupiter’s moon Io, the acceleration due to

At the surface of Jupiter’s moon Io, the acceleration due to gravity is g = 1.81 m/s2. A watermelon weighs 44.0 N at the surface of the earth. (a) What is the watermelon’s mass on the earth’s surface?...

Q: A small car of mass 380 kg is pushing a large truck

A small car of mass 380 kg is pushing a large truck of mass 900 kg due east on a level road. The car exerts a horizontal force of 1600 N on the truck. What is the magnitude of the force that the truck...

Q: World-class sprinters can accelerate out of the starting blocks with

World-class sprinters can accelerate out of the starting blocks with an acceleration that is nearly horizontal and has magnitude 15 m/s2. How much horizontal force must a 55-kg sprinter exert on the s...

Q: The upward normal force exerted by the floor is 620 N on

The upward normal force exerted by the floor is 620 N on an elevator passenger who weighs 650 N. What are the reaction forces to these two forces? Is the passenger accelerating? If so, what are the ma...

Q: Boxes A and B are in contact on a horizontal, frictionless

Boxes A and B are in contact on a horizontal, frictionless surface (Fig. E4.23). Box A has mass 20.0 kg and box B has mass 5.0 kg. A horizontal force of 250 N is exerted on box A. What is the magnitud...

Q: A student of mass 45 kg jumps off a high diving board

A student of mass 45 kg jumps off a high diving board. What is the acceleration of the earth toward her as she accelerates toward the earth with an acceleration of 9.8 m/s2? Use 6.0 × 1024 kg for the...