1.2 Balanced forces

• Natuurkunde / Scheikunde
• Middelbare school
• havo
• Leerjaar 1

1.2 Balanced and unbalanced

forces

Learning goals

• Recognise balanced and unbalanced forces.
• Name two things balanced forces can do.
• Name two things unbalanced forces can do.
• Calculate resultant force.

How do you show forces

You show forces with an arrow.

The length of a force shows the magnetitude.

And the direction of the arrow shows the direction of the force.

Balanced and unbalanced forces

• Balanced forces
• Unbalanced forces
• Resultant force

Balanced or unbalanced?

Balanced or unbalanced?

Resultant force

A resultant force, also called a net force, is a force equal to the sum of all forces applied to an object.  For example, a 3N force to the left and 10N force to the right gives a resultant force of 7N to the right.

Fingerspell

• Forces in the same direction add up.
  

• Forces in opposite direction cancel out.

The effects of:

Balanced and unbalanced forces

Stationary: When an object is not moving, standing still

Constant velocity: When an object is moving at a constant speed

Acceleration: When the speed of an object is increasing (or decreasing)

Stationary: When an object is not moving, standing still

Constant velocity: When an object is moving at a constant speed

Acceleration: When the speed of an object is increasing (or decreasing)

Stationary: When an object is not moving, standing still

Constant velocity: When an object is moving at a constant speed

Acceleration: When the speed of an object is increasing (or decreasing)

Stationary: When an object is not moving, standing still

Constant velocity: When an object is moving at a constant speed

Acceleration: When the speed of an object is increasing (or decreasing)

The forces on an object are 

balanced.

How does this effect its motion when...

• It is stationary?

• it is moving at a constant speed?

Balanced Forces

When an object is...

• stationary –> It stays stationary

• Moving –> travels at a constant speed.

The forces on an object are unbalanced.

How does this effect its motion when...

• it is stationary?

• it is moving at a constant speed?

Unbalanced forces

When an object is...

• stationary –> It starts moving

• Moving –> accelerates or decelerates

	balanced forces	Unbalanced forces
stationary objects
Moving objects

	balanced forces	Unbalanced forces
stationary objects	stays stationary	starts moving
Moving objects	keeps the same speed	accelerates/ decelerates

Working on exercises

Homework:

Do: textbook 1.2 - the yellow block exercises

Do: workbook exercises 1.2 inclusive E