work, scientifically speaking, is done on an object when a force is applied to move it a certain...
TRANSCRIPT
Work, scientifically speaking, is done on an object when a force is applied to move it a certain distance.
IMPORTANT! The distance (displacement) in this case is determined by measuring the difference from where the object started from to where it finishes, no matter what path it took. If a force is applied to move an object but there is no displacement, there is NO work done.
Displacement
2.0 m
3.0 m
3.0 m2.0 m
6.0 m
4.0 m
2.0 m3.0 m
Total Distance = 22.0 meters
Simple machines do NOT change the amount of
work done. Simple machines can make doing
work easier by lowering the magnitude of the force
applied by increasing the distance the force needs
to be applied over. Simple machine can also
change the direction of the force.
The work done is always the same!
2.0 N 10.0 Nm 5.0 m x =
NOTE: The distance in the formula is the distance the force is applied over, not the distance (displacement) of the object!
Usually Lowers
Doesn’t Change
Usually Increasesx =
1.0 N 10.0 Nm 10.0 m x =
0.5 N 10.0 Nm 20.0 m x =
1.Pulley 4. Screw
2. Inclined Plane 5. Wedge
3.Lever 6. Wheel and axle
Pulleys can either change the direction of the force or reduce the amount of force needed to do work by increasing the distance.
5.0 N
1.0 m
1.0 m
The magnitude and distance of applied force is the same. The direction is different!
F = 5.0 N
2.0 m
To use less force and still complete the same amount of work, a lower force must be applied over a greater distance.
5.0 N
1.0 m
F= 2.5 N
Inclined planes are the same as ramps.
8.0 m
2.0 m
10 N
Inclined planes make work easier by creating a longer distance for the object to travel while still accomplishing the same amount of work.
Without Ramp: Work = F x d = 10 N x 2.5 m = 20.0 Nm
Inclined planes are the same as ramps.
8.0 m
2.0 m
10 N
Inclined planes make work easier by creating a longer distance for the object to travel while still accomplishing the same amount of work.
With Ramp: Work = F x d = 2.5 N x 8.0 m = 20.0 Nm
LESS FORCE!
Inclined Plane
Inclined Planes
Load
Eff
ort
Fulcrum
2.0
m
2.0
m
Levers can change the direction of the force if the fulcrum is located in the middle of the lever arm.
LoadFulcrum
Eff
ort
2.0
m
6.0
m
Levers can also make work easier by lowering the force (effort) by increasing the applied distance.
Load
Effort
Fulcrum
Eff
ort
Load
Fulcrum
Fulcrum
LoadEff
ort
Wheel
Axle
Compound machines are machines that are
made of two or more simple machines.
Lever
Wedge
ScrewLever
Wheel & Axle
Pulleys
Lever
Lever
Wheel & Axle
Lever
Screw
Screw
Gear