Chapter 4 - Forces In One Dimension

Question 0

All accelerations are the result of an _________ _____ acting on an object.

Answer 0

Unbalanced force.

Question 1

In physics, a push or pull is called a _____.

Answer 1

Force.

Question 2

The objects or objects of interaction is called the _________.

Answer 2

System.

Question 3

What’s a contact force?

Answer 3

A contacts force exists when an object from the external world touches a system, exerting a force on it.

Question 4

What is a field force? Give an example.

Answer 4

Field forces are exerted without contact. An example of that is gravitational, magnetic, … Etc.

Question 5

What is a free body diagram?

Answer 5

It’s a physical representation that shows the forces acting on a system.

Question 6

What’s a net force?

Answer 6

The vector sun of all the forces on an object.

Question 7

Explain Newton’s first law.

Answer 7

An object that is at rest will remain at test, and an object that is moving will continue to move in a straight line with constant speed, if and only if the net force acting on that object is zero.

• acceleration = 0
• Fnet = 0
• object in equilibrium.

Question 8

Define inertia. Is it a force?

Answer 8

It’s the tendency of an object to resist change in velocity. No it’s not a force. Forces are results of interactions b/w objects; they’re not properties.

Question 9

When is the object in equilibrium?

Answer 9

If the net force on it is zero. An object is in equilibrium if it’s moving a constant velocity, too.

Question 10

Explain Newton’s second law.

Answer 10

A = Fnet/m 
If the object is at rest, it will start moving. If the object is moving with a constant velocity, then it will speed up, slow down, or change direction. 
- object not in equilibrium
- A =/ 0
- Fnet =/ 0

Question 11

Define weight.

Answer 11

It’s the gravitational force experienced by that object. It’s Fg = mg. With g called the gravitational field.

Question 12

Define drag force.

Answer 12

Force exerted by a fluid on an object opposing motion through the fluid.

Question 13

Define interactive pair.

Answer 13

Set of 2 forces that are in opposite directions, have equal magnitude, and act in different objects.

Question 14

Explain Newton’s third law.

Answer 14

All forces come in pairs. The two forces in a pair act on different objects and are equal in strength and opposite in direction.
F A on B = - F B on A

Question 15

Define tension.

Answer 15

A specific name for the force that a string or rope exerts.

Question 16

What’s a normal force.

Answer 16

It’s a perpendicular contact force that a surface ever on another surface.