Newtons Three Laws Of Motion

In the Video we learned about the Laws of Motion the laws of Motion are the Following:

1. In the absence of a net force, a body either is at rest or moves in a straight line with constant speed.
2. A body experiencing a force F experiences an acceleration a related to F by F = ma, where m is the mass of the body. Alternatively, force is equal to the time derivative of momentum.
3. Whenever a first body exerts a force F on a second body, the second body exerts a force −F on the first body. F and −F are equal in magnitude and opposite in direction.
   

Quoted from Wikipedia.

Works and Machines Questions page 81

1)The parts of a pulley are hub (or boss), the arms (or spokes) and the rim.
2) It is easier to use a pully system because the car engine would be very heavy to lift its easyer to pull a rope then lift it.
3) The Chain on a bike moves all the gears together once the pedals are used the gears move the wheels.
4) The Differance of high and low gear is low gear, the difference is the power (work/time). in High gear you need to pedal with more power.
5)

Works and Machines Questions page 80

1) Doing work is using a force to move an object. A Machine is anything which makes it easier to do work.
2) We are doing work we are pushing a mower cleaning our teeth cycling because these cause force, but we are not doing work when we are reading this page because it dosnt need force.
3) We must eat to keep working because we need the energy.
4) Spanners, pliers and canoppeners are all machienes because it makes work easier.
5) Levers, pullies, ropes, incline Plane, weage, are all simple machines.