mechanics final

What is the equation for work done?

E=Fd

work done= force x distance

(must be parallel, x cos theta if not)

What is work done measured in?

Joules J

What is the equation for GPE (Gravitational potential energy)

E= mgh

GPE= mass x grav fielf strength x height

\

What is the equation for Kinetic energy

E=1/2 mv^2

kinetic energy= 1/2 x mass x speed^2

If something falls, why don’t you need it’s mass to calculate its final speed, assuming ideal conditions?

1/2mv^2=mgh

1/2v^2=gh

\

If GPE at the top dos not equal KE at the bottom, where has the energy been lost?

Loat as work done against frictional forces (friction and air resistance)- increases thermal energy store of surroundings.

This energy can be used in E=Fd to find size of friction.

Why does braking distance quadruple if you double your speed?

e=1/2mv^2

What is the definition of internal energy?

The sum of kinetic energy and potential energy of an object/substance

What does distance/time equal

average speed