something that can change the velocity of an object
alway acts in the opposite reaction as to retard relative motion
when two objects are in close contact
is a unti of force which is 4.45N=1lb
when an object is at equilibrium all forces acting on it are equal to zero
depends more on the pressure between two surfaces rather than velocity
when a solid mass passes thru a liquid, gas or air vicous drag will occur. Viscous drag will increase as speed increases.
- aerodynamic shapes come in to play
-properties of the fluid also come into play
weight is equal to MG; mass x gravity
when you applhy pressure on a solid object, that object will bend but also push back with a force equal to one exerted on it.
tension can be measured by cutting a rope and introducing a spring scale
buoyancy acts in an upward direction on anything submerged in a liquid or gas.
An object with a weight greater than the booyancy of the fluid it is in will sink.
forces exist only in pairs
there are six simple machines
2. incline plane
5. wheel and axle
work is the force applied over a distance
Output ratio to inout ratio of work produced by a machine
whenever a force moves something over a distance. W=FxD
Force required to move 1 kilogram one meter in one second.
1kg x m/s
Mecahnical Advantage Formula
MA = Fl/Fe = load/effort
the force that actually produces horizontal movement when a force is appled at an angle.
ME= Wout/Win = work put out / work put in
a Force with both magnitude and direction
FeDe = FlDl
MA = Re/Rl
there are 3 types.
class 1- fulcrum between effort and load; dolly
class 2- Fulcrum on one end, with load between; wheel barrow, nutcracker
class 3- Effort in the middle of load and fulcrum; fisherman, tongs
plane set at and angle
MA = lenght / height
Woutput = load x height
Win= Force x lenght of ramp
A double inclined plane that moves to exert a force along the lenght of its sides to push two objects apart
-knife, ax, chisel
Wheel and Axle
wheel and axle
can be thought of as an inclined plane with a wedge wrapped around a cylinder.
forces are applied perpendicular to the groove
the pulley uses the principle of applying force over a longer distance. It also uses tension in the rope or cable.
MA of Pulley
De = Dl x supporting strands
E = Load / number of strands
W = F x D
liquids are nearly incompressible.
MA = Al / Ae
Aii / Ai = Di / Dii
Aii = diameter of larger circle
Ai = smaller
Di= Vertical distance of smaller
MA = # of teeth in load gear / # of teeth in effort gear
1 ft-lb/s = 550 hp
746 joules = 1 hp