Mechanics (Forces)

Question 1

What is “Force”

Answer 1

• Cause of DEFORMATION or a CHANGE IN VELOCITY
• Vector quantity
• Measured in Newtons (N) = (kg)(ms^-2)

Question 2

What is Newton’s 1st Law of Motion?

Answer 2

The Law of Inertia

• An object will remain at rest or travel with a constant velocity unless an external force acts on it

Question 3

What is Newton’s 2nd Law of Motion?

Answer 3

The Law of Force and Acceleration

• The resultant force is directly proportional to the acceleration
• F=ma

Question 4

What is Newton’s 3rd Law of Motion?

Answer 4

• The force that one mass exerts on another is equal in magnitude and opposite in direction to the resultant force that is acted on itself
• they must also be the SAME TYPE of force

Question 5

What is Translational Equilibrium

Answer 5

Translational Equilibrium is when the resultant (net) force of an object is zero. (all forces cancel out)

The object will either be:

• At rest
• moving with a constant velocity

Question 6

What is Friction?

Answer 6

the force that opposes the relative motion of two surfaces

• Always towards the opposite direction of the force of motion
• Caused by the microscopic unevenness of the two surfaces
• Proportional to the Normal reaction force (R) on the object:
  F(f) = μR

Question 7

What is Static Friction

Answer 7

When two surfaces are at rest, and friction is preventing motion

• The value changes depending on the force applied to it, resulting in zero resultant force
• In order to get an object to move on a surface, the force acting on it must be more than the maximum static friction force to get it to move

Question 8

What is Dynamic Friction

Answer 8

When two surfaces are moving, but friction is slowing it down

• Less than static friction
• is consistent regardless of velocity