Forces

1. T tension mg weight W = Mg weight T2 T1 Forces mass M In equilibrium T = mg If the pulley is smooth T1= T2

2. N R plank mg mg mg N F plank plank Reaction Forces In equilibrium N = mg Friction

3. Examples of other forces: • A person may push or pull an object • An engine could pull an object • Wind or air resistance may act • Water can provide an upthrust • Air causes lift and drag on an aircraft

4. Force Diagrams Normal reaction Normal reaction Tension Pull Normal reaction Weight Weight Resistance Engine force Normal reaction Air resistance Weight Weight Weight

5. Lift Engine force Drag Lift Upthrust Weight Swimmer Water resistance Wind Normal reaction Weight Air resistance Tension Weight Weight Push Force Diagrams

6. Forces on Mr Bean Lift Tension Wind Wind Weight of balloon & Tension Mr Bean's weight Forces on Weights Forces on Weightlifter Lift from weightlifter Normal reaction from floor Weight Weights (weightlifter & weights) Force Diagrams Forces on balloon

7. Forces on horse Forces on man Normal reaction from ground Normal reaction from ground Man’s force Horse resistance Tension Tension Weight Weight Forces on book Normal reaction Friction Desk Weight Force Diagrams

8. Forces on trailer Forces on car Normal reaction from ground Normal reaction from ground Tension & Resistances Resistances Tension Engine force Weight Weight Forces on bag Forces on tool box Tension Normal reaction from table Friction Tension Weight of bag Weight of tool box Force Diagrams