# Motion

• Created by: TAAAM
• Created on: 04-06-15 15:22
How can we describe motion? The speed of a moving object can be calculated if the distance travelled and the time taken are known. The faster an object moves, the steeper is the line representing it on a distance-time graph.
The equation When an object moves in a straight line at a steady speed, you can calculate its speed if you know how far it travels and how long it takes. This equation shows the relationship between speed, distance travelled and time taken:
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Speed=distance traveled/ time taken
For example, a car travels 300m in 20s. Its speed is 300 ÷ 20 = 15m/s.
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What are forces? Forces occur when there is an interaction between two objects. These forces always happen in pairs – when one object exerts a force on another, it always experiences a force in return.
One force causes another Sometimes a force is produced as a response to another force – these are not the same as interaction pairs. A book on a table has a downwards force (its weight) due to gravity. This downwards force, pushing on the table, pro
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Friction Another common force is friction. When two surfaces slide past each other, the interaction between them produces a force of friction.
When you push backwards on the floor with your foot, the friction between your foot and the floor exerts a backwards force on the floor. The other force of the interaction pair is the floor pushing your foot forwards. The floor does not move, but you
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What is the connection between forces and motion?The momentum of an object is its mass multiplied by its velocity. The larger the mass and velocity the larger the momentum. Forces change momentum - the larger the force the more quickly the momentum
changes A car or bicycle has a driving force pushing it forwards. There are always counter forces of air resistance and friction pushing backwards.
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You need to know how these forces compare if you are to predict what will happen to the speed of a moving object. If the driving force is greater than the counter forces, there is a resultant force forwards. This will make the car speed up.
If the driving force is less than the counter forces, there is a resultant force backwards. This will make the car slow down.
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## Other cards in this set

### Card 2

#### Front

For example, a car travels 300m in 20s. Its speed is 300 ÷ 20 = 15m/s.

#### Back

Speed=distance traveled/ time taken

### Card 3

#### Front

One force causes another Sometimes a force is produced as a response to another force – these are not the same as interaction pairs. A book on a table has a downwards force (its weight) due to gravity. This downwards force, pushing on the table, pro

#### Back ### Card 4

#### Front

When you push backwards on the floor with your foot, the friction between your foot and the floor exerts a backwards force on the floor. The other force of the interaction pair is the floor pushing your foot forwards. The floor does not move, but you

#### Back ### Card 5

#### Front

changes A car or bicycle has a driving force pushing it forwards. There are always counter forces of air resistance and friction pushing backwards.

#### Back 