Mechanics M17-M24 Flashcards
Define ‘work done’?
Work is the energy transferred to or from an object.
Define ‘GPE’?
GPE is the energy of an object due to its position in a gravitational field.
Define ‘KE’?
KE is the energy of an object due to its motion.
Why does the formula for work contain “cosθ”?
Work done = F x s x cos(theta)
What is represented by the area under a force-displacement graph?
The work done.
Define power?
Power is the amount of energy transferred in a certain time period.
What is the ‘F’ in P=Fv
Power = force x velocity.
What is momentum?
Momentum is a vector quantity - it has both a magnitude and a direction
Momentum is also the product of the mass x velocity.
When is it conserved?
When there are no external forces acting on the collision.
What is an elastic collision?
There is no net loss in kinetic energy in the system as a result of the collision. Both momentum and KE are conserved.
Define ‘impulse’?
The overall effect of a force acting over time. Impulse = the change in momentum = force x time.
What is represented by the area under a force-time graph?
force x time = change in momentum = impulse.
What is Newton’s 3rd law?
Action reaction forces acting on the same body in opposite directions.
Give some examples of Newton’s 3rd law
Gun Firing: when someone fires a gun, the action force pulls the bullet outside the gun, and the reaction force pushes the gun backward.
Hand on table.
How is impulse relevant in transport safety?
If there is a great force experienced by a person, by increasing the duration/time of the said force felt, the smaller the impulse, and more safe the person will feel. To do with the airbags, seatbelts and crumple zones in cars.
