Chapter+6+Force+and+motion

**Forces**
Forces are pushes or pulls. Forces can make things happen. They can: 1. start an object moving 2. slow down a moving object 3. make an object change shape. Arrows we draw that point in the direction of a force. The length shows the size of the force.

Types of forces; You name it each.
 * U................ || *The force caused by water pushing up against an object. ||
 * || *A force that stops things falling through solid objects. When you sit on a chair, your weight is balanced by the reaction force from the chair. ||
 * || *The force that pulls everything towards the centre of the Earth. The other planets, the Moon and the Sun also pull things because of gravitational attraction. ||
 * || *The force produced by a magnetic field. ||
 * || *A force that opposes motion. It happens when things rub against each other. It stops things moving easily. ||

Use these words to fill the gaps.
 * move ||  ||   || change in speed ||   ||   || slows down ||   ||   || unbalanced ||   ||   || move faster ||   ||   || bigger ||

If one force on an object is bigger than another, the forces are ................................................. .

When unbalanced forces act on an object it starts to ...move... in the direction of the ...bigger.......force. It gets ..the change in speed.. .

If the bigger force is in the same direction as the object is moving, the object .............................................................................

If the bigger force is opposite to the direction the object is moving, the object ............................................................................ .

A............ ............................. is a type of friction force, caused by the car moving through the air.
 * Complete below sentences

For a car, the force of the ...................................... is in the opposite direction to the ................. ............................ is the force acting when the driver applies the brake.

Two forces of the same size pulling in opposite directions. An object floats when the upthrust is equal to its weight. It stays on the top of the water. An object sinks if its weight is bigger than the upthrust. It moves down in the water.
 * Balanced Force**

Forces pushing in different directions when one force is bigger than the other. An unbalanced force makes the object move or speed up or slow down.
 * Unbalanced Force**

To move an object to the right … Once an object is moving at a steady speed … ||  ||   ||   ||   ||   || … the pushing force and the friction force are balanced. … the forces acting on it must be unbalanced. … you must push it to the right. ||
 * Complete sentences by matching the above phrases.
 * To make an object begin to move …

Plenary: Criss Cross Puzzle

Lesson on Wednesday

Starter : 1. Use these words to fill the gaps. a If the forces are ...................................... an object will not move.
 * **water opposite** ||  || **float** ||   || **upthrust** ||   || **balanced** ||

b Balanced forces are the same size and pull in ...................................... directions.

c When you put an object in water, the ...................................... pushes upwards on the object. This push is called .......................................

d If the upthrust on an object is the same size as its weight, the object will ...................................... .

2 This balloon is floating in the air. Look carefully at the diagram. Which arrow shows the upthrust? Circle the arrow.

weight mass gravity newtons (N) kilograms (kg) || ● ● ● ● ● ● ||  ||   ||   ||   ||   || ● ● ● ● ● ● || How much stuff something is made of The pull of the Earth’s gravity on something. A push or a pull. Weight is measured in these. The units of mass. The force that makes something fall to the ground. ||
 * Match the words to the descriptions.
 * force


 * Objectives : Investigate stretchiness of springs**

Test 2 different springs for stretchness.

Describe your results.

Make predictions based on your results

Aim: To find out how stretchy a spring is

Length after adding masses - Starting length || Newtons(N) || Graph : 1. Extension(cm) against Masses added(g) 2.Newtons(N) against Masses added(g)
 * Masses added(g) || Length of spring(cm) || Extension (cm)
 * 0 ||  ||   ||   ||
 * 50 ||  ||   ||   ||
 * 100 ||  ||   ||   ||
 * 150 ||  ||   ||   ||
 * 200 ||  ||   ||   ||
 * 250 ||  ||   ||   ||

Conclusion: What happened to the extension as more masses were added? When the number of masses was doubled?

Extension : Write a list of the factors you would need to control in order to make it a fair test. Have a look at another spring - compare it to how your first spring felt when you tried to stretch it - how do you think a graph for that spring would look. try to stretch the line you would see in your book.


 * **Mass in Grams** || **Mass in Kilograms** || **Weight in Newtons** ||
 * Plot a Weight(N) against Mass(Kg) graph.
 * Plot a Weight(N) against Mass(Kg) graph.
 * Plot a Weight(N) against Mass(Kg) graph.
 * Plot a Weight(N) against Mass(Kg) graph.
 * Plot a Weight(N) against Mass(Kg) graph.

1. Use your graph to find out the weight of A, and the mass of B.

Weight of object A = ............. newtons Mass of object B = ............. grams

Check the weight of A and the mass of B on the balances.

Compare the mass and weight for objects A and B. Decide how much bigger the weight (in newtons) is than the mass (in kilograms).

2. Complete the sentences below.

a Weight is ............. times the mass.

b When mass is 1 kg, weight is ............. N.