Physics questions - NEWTON's first law?

Question

An obect in motion keeps going because it has ______ (one word answer).

Inertia is/is not a force.

inertia would be best described as... (CHOOSE ALL THAT APPLY)
mass
resistance to change in velocity
the tendency to maintain constant velocity
the force of gravity
resistance to acceleration
a force within the object
a property of matter

A piece of cheese is at rest. A gerbil pulls to the left with 1.5 N at the same time as a mouse pulls to the right with 1.5 N.
what is the net force on the piece of cheese?
What does the cheese do in this situation? choose ALL that apply:
moves with constant non-zero velocity
accelerates at a constant rate
remains at rest
maintains constant velocity
speeds up
moves with a changing velocity
slows down

Answer 1

Inertia

Inertia is not a force.

a property of matter

The following are a consequence of the property of matter known as inertia:
resistance to change in velocity
the tendency to maintain constant velocity
resistance to acceleration

Assuming ideal conditions:
The net force on the cheese is zero.
The cheese:
accelerates at a constant rate
remains at rest
maintains constant velocity

In an actual situation, I doubt the cheese would survive such forces. I believe the cheese would be rent in twain.

Answer 2

An object in motion keeps going because it has ______ inertia.

Inertia is not a force.

inertia would be best described as...
resistance to change in velocity
the tendency to maintain constant velocity
resistance to acceleration
a property of matter

A piece of cheese is at rest. A gerbil pulls to the left with 1.5 N at the same time as a mouse pulls to the right with 1.5 N.
what is the net force on the piece of cheese?

1.5N - 1.5N = 0

What does the cheese do in this situation?

remains at rest

Or breaks into tender mouthfuls.

Answer 3

Inertia is a type of force. Specifically, it is the force required (resistance) to change the velocity of a mass. This is the answer to your first question.

What makes this term confusing is that in one sense there is no such thing as different types of forces. All forces feel the same, will register the same way on a scale and are measured in the same units (e.g. pounds, newtons). What -is- different is how the force is created.

An intertial force is created by changing the velocity of an object (accelerating an object). A centrifigal force is created by spinning an object. A magnetic force is created through magnetic attraction of two objects. But each of these different forces would still be measured in pounds.


The net force on the cheese is the sum of the forces acting on it. Since there are two forces pulling on it in opposite directions, the net force acting on the cheese is zero (you have to include the direction of the force, so pulling to the left is a negative 1.5N, while pulling to the right is a positive 1.5N). Now suppose the mouse pulled a little harder, so that it's pulling with 2.0 N of force to the right. The net force on the cheese would be +2.0 + (-1.5) = 0.5 N to the right, and the cheese would start to move towards the right.

Now, with 1.5N pulling the cheese to the left, and another 1.5 pulling it towards the right, the net force is zero. But, within the cheese itself, the pulling introduces internal stresses; you would expect the cheese to stretch out a little. But it will not move, since the net force on it is zero.

Hope this helps,

-Guru

Answer 4

An object in motion keeps going because it has inertia.

Inertia is not a force.

Inertia would be best described as
resistance to change in velocity and
tendency to maintain constant velocity.

The cheese starts at rest. The mouse and the gerbil exert identical sized forces in opposite directions. There is no net force on the cheese, so the cheese remains at rest.