Work, energy, power

Work done definition

Equal to the force multiplied by the distance moved in the direction of the force (Energy is transfer)(Change in potential energy or kinetic energy)

Work done equation and other equivalent

Fs (distance)

(mg)s

(ma)s

(mg)h= potential energy

joule definition

The work done when the force of one Newton moves an object through a distance of 1 m in the direction of the force

How do you calculate the weight if the force and displacement are not in the same direction?

W=F cos theta x s

Energy definition

Capacity to do work (scalar)

Gravitational potential energy definition and equation

Energy and object has because of its position

Ep=mgh

Kinetic energies definition and equation

Energy an object has due to its motion

½ mv²

How do you calculate the work done against friction and how do you find the average?

Potential energy minus kinetic energy, then you divide it by the distance given

What is the energy is equal to

Change in potential energy equals a change in kinetic energy so if one of them is gain, the other one has lost vice versa

What is the area in a force displacement

Work done

How do you find the velocity using the change in EP equals change in EK equation? What does the velocity show?

Mgh=1/2mv²

Gh=1/2 v²

V=square root (2gh)

Velocity is independent of mass

In a swing pendulum diagram, what is the length equal to what is the change in height equal to?

The length is both the length given plus the height from the pendulum length to the centre of the ball.

Changing height = length minus length cos theta

If it is initially at rest, what is the final work done

From the work done theorem, it is the change in EK or change in EP so The final work done will just be the final EK equation or EP equation

What is the conservation of energy?

Energy cannot be credited or destroyed only transferred

Power definition and it’s different equation

Rachel doing work or energy transfer

P = E/t

P = W over t

P=Fs/t

P=Fv

P=Ep equation/t

P=Ek equation/t

Watt Definition and unit equivalent

Equal to one joule transferred every second

W=1Js^-1=kgm²s^-3

What is efficiency never?

It is Never greater than 100% or 1.0

Efficiency equation

Useful output over input multiplied by 100

This is for both power and energy

What is the equation for frictional

Useful energy over distance

How do you calculate the volume per unit time

First work out the power or energy input, Then work out the mass per unit time using P = E/t=mgh

Then calculate the volume from mass per unit time divided by density

How do you calculate the ratio Of kinetic Energy of P and Q if P has a mass 10 times than Q

How do you calculate mass from overall efficiency, height, and input power?

First calculate power output then use P=E/t=mgh/t then rearrange to make mass the subject