Mechanics Flashcards
Define ‘work done’ by a force
Force x distance in the direction of the force
State the unit of work done
Joules, J
Define acceleration
Rate of change of velocity
State the ‘Principal of conservation of energy’
Where the total energy of a closed system remains constant
State the unit of acceleration
m s^-2
What is the SI unit of distance
Meters, M
What is force measure in?
Newtons, N
Define ‘Breaking distance’
The distance travelled by a car after the brakes are applied until the car stops
Describe how seat belts reduce force on a driver during an impact
- Increases time of impact
- Increases distance travelled by the driver
- Smaller deceleration/acceleration
- Force is smaller (F=ma)
Define ‘moment of a force’
Force x perpendicular distance from point
State two conditions that apply when an object is in equilibrium
Net force=0
Net moment= 0
Net talk=0
Define ‘centre of gravity’
The point where weight appears to act
State ‘Hooke’s Law’
extension is proportional to the applied force
Define ‘Youngs Modulus’
Stress/strain
What are the conditions of Youngs Modulus
- Elastic limit is not exceeded
- Hooke’s law is obeyed
