Physics Chapter 4 Questions – Flashcards

When surfaces slide or tend to slice over one another, a force of friction acts. When you apply a force to an object, friction usually reduces the net force and the resulting acceleration.

If an object is to move at a constant velocity, a force equal to the opposing force of friction must be applied so that the two forces exactly cancel each other. No friction exists on a crate that sits at rest on a level floor. But, if you push the crate horizontally, you'll disturb the contact surfaces and friction is produced. If the crate is still at rest, then the friction that opposes motion is just enough to cancel your push.

Like stated before, the force you need to exert would have to equal the opposing force of friction.

There are times when weight corresponds to our unconscious notion of inertia. For example; If you are trying to determining which of two small objects is heavier, you could shake them back and forth in your hands or move then in some way instead of lifting them. In doing so, you are judging which of the two is more difficult to get moving; feeling which of the two is most resistant to a change in motion. You are really comparing the inertias of the two objects. Mass is a measure of the inertia of a material object.

Mass and weight often get confused with each other. People believe that mass (which is the matter of things) often means the same thing as weight (their gravitational attraction to the Earth). These two concepts are totally different things.

In the absence of acceleration, mass and weight are directly proportional to each other. If the mass of anobject is doubled, its weight is also doubled; if the mass is halved, the weight is halved. Because of this, massand weight are often interchanged. However, mass is more fundamental than weight; it is a fundamentalquantity that completely escapes the notice of most people. Weight varies with location.

The acceleration would also be tripled. Acceleration is directly proportional to the net force

If the net force is applied while the mass of the sliding block is tripled, then the mass is decreased by one and a half.

Motion under the influence of gravitational pull only.

6 N and then 0 N.

First, it depends on the frontal area of the falling object that is, on the amount of air the object must plow through as it falls. Second, it depends on the speed of the falling object.