Forces

Question 1

What is a force, SI unit

Answer 1

A force is a push or pull motion an object exerts on another. Newton (N)

Question 2

How can force affect motion

Answer 2

Force can produce, decrease, increase, stop and change direction of motion

Question 3

Examples of contact forces

Answer 3

-Frictional force

-Tensional force

-Normal contact force

Question 4

Examples of non-contact forces

Answer 4

-Gravitational force

-Magnetic force

-Electric force

Question 5

Newton’s first law: Balanced forces (inertia)

Answer 5

-Every object will continue in its state of rest or uniform motion in a straight line unless a resultant force acts on it

-Reluctance of a body to change its state of rest or state of motion

-Mass affects inertia, higher mass = higher inertia

Question 6

Newton’s second law: Unbalanced forces (accelerate, decelerate)

Answer 6

-When a resultant force acts on an object of a constant mass, the object will accelerate in the direction of the resultant force. The product of the mass and acceleration of the object gives the resultant force

-Force in direction of motion = Accelerate

-Force against direction of motion = Decelerate

Question 7

Newton’s third law: Interaction between two bodies

Answer 7

-For every action, there is an equal and opposite reaction

-Occurs in pairs

-Equal in magnitude

-Direction of forces are opposite

-Forces act on 2 different bodies

Question 8

Vector diagram methods

Answer 8

-Parallelogram method

-Head-to-tail method

-Resultant force is from start to end

Question 9

Effects of a force: Zero acceleration

Answer 9

Zero acceleration means the object can be stationery or moving with a constant velocity (does not mean no forces are acting on it)

Question 10

Friction

Answer 10

-Friction is the contact force that opposes or tends to oppose motion between surfaces in contact

-Result of irregularities of surfaces

Question 11

Positive and negative impacts of friction

Answer 11

Positive:

-Cars are able to slow down when needed
-Prevents humans from slipping while walking

Negative:

-Objects will suffer wear and tear
-Could cause humans to trip

Question 12

Free body diagrams (skip to answer)

Answer 12

Free body diagrams are simple diagrams with arrows that represent forces acting on individual objects

Question 13

Formula for resultant force

Answer 13

F = ma

Resultant force = mass x acceleration