Physics chapter 8 Flashcards
What does work done mean
Energy transferred
Everyday examples of work done
- Walking upstairs
- Lifting heavy objects
- Pulling a sledge
When is work done
When objects move in the same direction as the force
When is work not done
- When direction of force and movement is different.
2. No movement
Examples of no work done
When weightlifter is holding weights above their head as there is no movement
What are the purposes of a spacecraft
- Communications
- Earth observation
- Meteorology
- Navigation
- Space colonization
- Planetary exploration
- Transportation of humans and cargo
What is the formula for Work
Work= Force x Distance
SI unit for work
Joules (1 joules= 1Nm= 1kgm^2/s^2)
Define power
The rate at which work is done. The shorter time he does it, the greater his power
2 ways of increasing power
- Increase the weight while keeping the same time
2. Lift an object more quickly
SI unit for power
Watts (1 watt= 1 joule/s)
Formula for power
Power= Work/time
p=W/t=Fd/t
What’s another way of saying 1000W
1kW (killowat)
How much is a megawatt
1,000,000 watts
1MW
Formula for kinetic energy
Kinetic energy= 1/2mv^2
