GCSE Physics - Forces and Shape

Forces are pushes and pull and they can change the way an object is moving or change the shape of an object

Forces: Reaction, weight (gravitational), upthrust, friction, drag, magnetic and electrostatic

Force is a vector and is measured in Newtons (N)

More than one force may act on an object

If the forces on an object are balanced, or if no force is acting on the object, the way it is moving will not change

If the forces acting on an object are unbalanced, the way it is moving will change

Friction is a force that acts to oppose the motion of an object

Friction also act when an object moves through a liquid or a gas

Friction is essential in certain situations but in other it wastes energy and causes wear

Springs and Wires:

• Springs change their length when a force acts on them and return to their original length when the force if removed
• This is true as long as you don't overstretch them

Hooke's Law:

extension of spring is directly proportional to the force applied to spring

Hooke's Law only applies if you do not stretch a spring too far

Elastic Limit - the point where the spring will stretch more for each successive increase in load force. After this point, the spring will change shape permanently

 Elastic bands do not obey Hooke's Law