Presentation on theme: " Forces are contact forces or field forces. When two bodies are in contact with each other, contact forces can result e.g. friction, twisting, pulling."— Presentation transcript:
Forces are contact forces or field forces. When two bodies are in contact with each other, contact forces can result e.g. friction, twisting, pulling or pushing forces.
Forces are contact forces or field forces. Field forces (non-contact forces) work over a distance e.g. gravity, electrostatic forces and magnetism.
A force can... make a moving object stop. cause a stationery object to move. change speed of moving object. change direction of moving object. change shape of object. have no effect at all.
Force of attraction that two bodies have on each other as a result of their mass. 1.The bigger the mass, the stronger the force of attraction. 2.The smaller the distance the stronger the force.
MASS vs WEIGHT Mass stays the same, weight different on earth and moon Weight on Earth calculated using formula: F = mg F = force (gravitation), m = mass, g = gravitational accelleration of 9,8 m/s 2. g on moon = 1,6 m/s 2 Weight of 50 kg person on Earth = 50 x 9,8 = 490 N Weight on moon? 50 x 1,6 = 80 N
Charge cannot be created or destroyed, it can only be transferred or distributed.
Like poles (N and N, or S and S) repel each other. Opposite poles (N and S) attract each other.
We know that the apple probably didn’t fall on Newton’s head, but a falling apple made him think about gravity... as well as many other concepts.