Forces and Energy

Forces and Energy

1. A resultant force shows the combined effect of several forces. It makes an object accelerate (change speed or directiion)

2. The stopping distance of a vehicle is thinking distance plus braking distance.

   • SD = TD + BD

3. Moving objects reach a terminal velocity (top speed) when drag forces matches driving forces.

4. Momentum is mass x velocity. It is conserved when objects collide of explode apart if no external forces act.

   • Momentum = Mass (kg) X Velocity (m/s)

5. A force transfers energy when it does some work on an object.

6. Objects gain gravitational potential energy if they are lifted up. Moving objects have kinetic energy. Stretched of squashed elastic objects store elastic energy.

7. The speed of an object can be found using a distance time graph. The acceleration and distance traveled can be found using a velocity time graph.