Force Diagrams

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Slide 1

Force Diagrams

Slide 2

Forces

We know that a force can be a push or a pull acting on an object

There is a good chance that 2 forces can be acting on an object at any one time

Examples:

Lifting something

Dragging something

Floating Globe

Slide 3

Balanced Forces

If two equal forces are applied to an object in opposite directions, the object does not move / or moves as a constant speed. This is called balanced forces.

Slide 4

Unbalanced forces

If two unequal forces are applied to an object in opposite directions, the object does move. This is called unbalanced forces.

And someone will win!!

Slide 5

Unbalanced Forces

If the forces acting on an object are not balanced then the object with either:

Speed up

Slow down

Change direction

Chance its shape

Fill in the Gaps sheet

Slide 6

We can use force diagrams to show this:

4N

7N

The block has 2 opposing forces being applied to it:

7N to the right and 4N to the left. They are Unbalanced Forces.

To Calculate the Resultant Force (Fr),

subtract one from the other: 7N – 4N = 3N to the right

3N

Slide 7

Problem

A man of mass 75kg has a weight of 750N. This 750N will act downward on the table and the table will exert a 750N force upwards on the man. The forces are balanced.

What would happen if the upward force were less than 750N?

Force down 750N

Force up 750N

Slide 8

Your go:

Collect Sheet: Drawing Force diagrams, fill in sheet finding Fr

Do Q6 p103 of text book

Lets have a tug of war!!

Slide 9

More on Balanced and Unbalanced Forces:

Collect and complete the following worksheets:

More on Balanced and Unbalanced forces

Floating and Sinking (Read p101)

Parachutes (Read p101)

Extension Work:

Text book: Starting Science for Scotland Book 2, Read p22, Ans Q1-4

Base Jumping