a force is best defined as ---

A student pushes against a wall with 20 N of force and the wall does not move. In this situation, the wall exerts --

Which change would require more force to pull the wooden block up the ramp?

Oliver stepped onto a three-car subway train with standing room only. What caused him to fall backward into other riders when the train suddenly moved forward?

Which law of motion predicts that a moving hockey puck will continue to move in the same direction at the same speed unless acted upon by another force?

Which law explains the relationship among mass, force and acceleration?

The force of an object, with a certain mass accelerating at a certain rate, can be determined by using the equation below.

force = mass x acceleration

Which object would have the greatest force?

Which of these would be different for an object if measured on the Earth and on the Moon?

The diagram below show the forces acting on a soccer ball.

In which of the diagrams will the ball remain motionless?

In the diagram below, a girl sits on a sled and slides down a hill of snow. Which arrow represents the force of friction opposing the motion of the sled down the hill?

Which of these examples best illustrates Newton's Second Low of Motion?

Which setup below would require the least force to lift a 100-gram mass a distance of 10 centimeters?

According to Newton's Third Law of Motion, if Mike pushes down on the springboard to being his dive, what is the reaction force?

Which principle best explains why the sprinkler spins?

Ana pushed on a big rock in her back yard. She was unable to get it to move because she did not -

Many bicycles use a hand brake to control their speed. When the brake is engaged, a rubber pad presses against the tire. What force of motion does the hand brake rely upon to slow the bicycle?

Which of the following situations is an example of Newton's third law of motion?

In a head-on collision, a person who is not wearing a seat belt continues to move forward at the original speed of the car because of -

A recent space shuttle mission carried a piece of cargo that had a mass of 122 kg with a weight of 1195.6 N. While orbiting the Earth, the astronauts weighted the equipment again and found it to be 24.4 N.

What was the mass of the equipment at this point?

Two school classes are playing tug-of-war with a rope. One class pulls on the rope with a 75 N force to the left, while the other pulls with a 40 N force to the right. Which two statements describe this situation?

$$s=\frac{d}{t}$$  

Nicki rides her bike at a constant speed for 6 km. That part of her ride takes her 1 hour. She then rides her bike at a constant speed for another 9 km. That part of her trip takes her 2 hours. What is her average speed?

Do you believe that you are pulled towards your science book, a bunch of grapes in your lunch, and your school building because of universal gravitation? Which two statements about universal gravitation are true?

Pam’s family is clearing some land, and there is a large boulder sitting on top of the ground. Even with the entire family pushing on it, they cannot move it. Which type of friction exists between the boulder and the ground?