level: Momentum + Moments
Questions and Answers List
level questions: Momentum + Moments
| Question | Answer |
|---|---|
| Define momentum | Momentum is the product of mass and velocity of an object |
| Whats the equation for impulse | Force x Change in time = change in (mass x velocity) |
| What can be said about momentum where no external forces act | Momentum is always conserved Momentum before an event is equal to the momentum after |
| Whats is impulse | Change in momentum |
| Whats the area under a force-time graph equal to | Change in momentum = Impulse |
| State some car saftey features, explain what they are Then explain how these help car saftey and explain how our understanding of momentum has helped us | Crumple zones, which crumple upon impact Seat belts which stretch upon an impact Air bags all of which increases the impact time of the car or the passenger This causes the force exerted on passengers to decrease meaning they are less likely to be seriously injured As Force = (change in (mass x velocity)) / change in time So longer time means less force |
| State the principle of moments | When a body is equilbrium Sum of anticlockwise moments = clockwise moments About the same point |
| For a moment question If the object which is applying a force isnt described as a particle, but rather as being a set distance in length What must be done to this before calulating the moment | Half the length of the force applying object |
| State what is meant by the centre of mass of an object | Point at which all the objects mass acts |
| Define a couple | a pair of equal and opposite coplanar forces |
| Define the moment of a couple | force × perpendicular distance between the lines of action of the forces |
| Define coplanar forces | Forces on the same plane |
| Whats the unit for momentum | kg⋅m/s |
| Whats the unit for moments | Nm |
| Whats the equation for momentum? | = mass x velocity |