AIM: ? OBJ: Given notes and activity sheet SWBAT with 70% accuracy DN: ACT: HW:

Force Force = push or pull; described by strength (N) and direction Unit of Force = Newton (N); where 1N = 100 g Force Instrument: force meter/spring scale (N) Force is represented as an arrow (with direction) longer arrow ~ greater force

Combining Forces Net Force = combining forces if forces are in the same direction, you add together to produce a net force. if forces are in opposite directions, you subtract to produce a net force in the direction of the larger force. if opposing forces are of equal strength, there is no (zero) net force.

Unbalanced Forces Unbalanced forces occurs when a net force is present causing a change in the object’s motion. if two unbalanced forces are in the same direction, the net force is the sum of the forces. if two unbalanced forces are in the opposite directions, the net force is the difference between the forces.

Balanced Forces Balanced forces occurs when equal (strength) forces are acting in opposite directions. The net force is zero. Balanced forces does not change the object’s motion. 500 N 500 N 10,000 N 10,000 N

Efficiency Efficiency of a machine compares the output work to the input work. Maximum efficiency is 100% but all machines have an efficiency of less than 100% because some work is wasted due to friction (heat loss). To calculate efficiency the following formula is used: Efficiency = Output Work x 100% Input Work

Force