Work Done, Moments and Momentum. Flashcards
How do we calculate the Work Done?
Work Done = Force x Distance
How do we calculate Power? (Name both equations)
Power = Work Done / Time OR Power = Force x Velocity
What’s the area underneath a force-displacement graph equal to?
Work Done.
What is the principle of conservation of energy?
Energy cannot be created or destroyed.
When we ignore frictional forces, what two equations can equal each other?
Ke = GPE
What is a moment?
A moment is the force of an object multiplied by the perpendicular length from the pivot to the point of action.
How do we calculate momentum?
Momentum = Mass x Velocity
What are the two types of collisions?
Elastic and Inelastic.
What happens in an elastic collision?
Momentum and Kinetic Energy are conserved.
What happens in an inelastic collision?
Momentum is conserved, but some of the Kinetic Energy is converted into other forms.
How do we know if a collision is inelastic?
If the objects stick together or if the Kinetic Energy is different to before the collision.
What is impulse?
The change of momentum on an object when the object is acted upon by a force for a specific time.
What is the area underneath a force-time graph?
The impulse.
How can a force-time graph show us collisions?
A steeper gradient will show us collisions that had more force acting upon them.
Give three examples of car safety devices.
Crumple zones, air bags and seat belts.
What are car safety devices designed to do and why?
They are designed to increase the amount of time that the collision takes so that the force that is exerted upon the person is smaller.
What’s the definition of power?
The rate of work being done.
What’s the definition of energy?
The ability to do work.
What’s the equation for Kinetic Energy?
KE = ½mv²
What’s the equation for Gravitational Potential Energy?
GPE = m x g x h
What is potential energy?
Energy held by a body because of it’s position or arrangement.
What is the equation for impulse?
FΔt = ΔP
What is the principle of conservation of momentum?
Force before a collision = Force after a collision
What is a perfectly inelastic collision?
A collision where one of the objects will group to the other one after a collision.
