# Physics GCSE-Edexcel

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Section 1-Froces and motion

MOVEMENT AND POSITION

distance time graphs- gradient indicates speed, straight line-constant speed, horizontal line indicates that the vehicle is stationary, neggative line- changed direction of the car. Velocity time graphs, gradient indicates acceleration, straight line- constant acceleration, horizontal line- constant speed, negative-deceleration.

• Average speed=Distance/Time m/s
• Acceleration=V-U/time m/s2
• The area under a velocity time graph is its area

FORCES/MOVEMENT/SHAPE

• Forces are pushes and pulls of one body on another
• Various types of forces include
• Friction- the force that opposed motion
• Air Resistance(Drag)- the friction caused by the object through air - Increases with speed
• Weight- The force due to gravity
• Viscous Drag- the friction between an object through liquids and gases
• Magnetic- The force between a magnet and another magnet (ferrous object)
• Electrostatic- The force between charges, different charges
• Upthrust- Upward force liquids/gases exert on objects

Balanced/Unbalanced Forces- When the upward acting force equals the downward acting force they forces are said to be balanced. When either the upward or the downward force in unequal , the forces are unbalanced and there is a resultant force acting in the direction of the bigger force. Unbalanced forces make an object accelerate/decelerate or change the direction in which theyre moving.

HOOKES LAW

• The extension of a spring is directly proportional to the force acting on it.
• The straight line represents the way the helical spring will return back to itr original shape unless it is pushed beyond its ELASTIC LIMIT, in which case it will not.
• Helical Springs, the force is on the vertical axis/extension on the horizontal, for wires/elastic bands the force is on the horizontal axis. Rubber bands to do not obey hookes law and have a (S) shaped graph.

NEWTONS SECOND LAW- Force=mass*Acceleration meaures in Newtons

Acceleration is directly proportional to force provided the mass is constant. This means a greter force contributes to greater acceleration, bigger masses need more force in order for them to accelerate.

Friction/Braking relating to the law

• The stopping distance is the combined thinking distance plus the braking distance.
• In order to come to rest, the car needs great deceleration, meaning a large force needs to be applied on a low mass. You cannot however conviniently change the mass of the car, and overbraking causes the car to skid.
• Thinking distance is affected by the state of the driver influenced by things like tiredness, alcohol, drugs, weather condition.
• The braking distance is affected by the condition of the road such as icy, wet and the condition of the tire- worn out tire.

ACCELERATION DUE TO GRAVITY

• All objects have the same speed of acceleratio due to gravity without the pressence of air.
• Its is 10m/s2 on Earth and the Weight is usually 10N/kg.
• Weight=mass * Gravitational…