Momentum, moments and Hookes Law Flashcards
What is the equation linking mass velocity and momentum
momentum = mass x velocity
p = mv
Explain the conservation of momentum
In any collision, the total momentum before is always equal to the total momentum after
Equation linking force momentum and time
Force = momentum change
time
In a collision how do you decrease the force
Increase the time
Name 3 safety features of a car
- Air bags
- Crumple zone
- Seat belts
What is the centre of gravity
The point from which an objects weight appears to act
How do you make an object more stable
- Larger base area
- lower centre of gravity
What is the principle of moments
A beam balances if thee sum of the clockwise moments equals the sum of the anti-clockwise moments
Equation for moments
Moment = force x distance from pivot
Moment = F x d
Units for momentum
kgm/s
Units for moments
Nm
How do you increase a moment
- Increase the force
- Increase the distance from the pivot
Hookes Law definition
The extension of a spring is directly proportional to the load
Define elastic limit
The elastic limit is the point at which the spring no longer obeys Hookes Law so when the load is removed it won’t return to its original length
Explain the method to the hookes law practical
1) Set us as diagram
2) Put zero on rule level with bottom of the spring
3) Add 1N on
4) Read extension at eye level using cocktail stick help across
5) repeat
How is the extension affected if the springs are in parallel
The springs will share the load, so they will extend half as much a single spring
How is the extension affected if the springs are in series
The springs extend twice as much as a single spring
