Physics kinematic and work/power Flashcards
Force of gravity >F drag
Person accelerates downward
Fg=Fdrag
Terminal velocity is reached so person travels at constant velocity
Mass
Scalar and measure body inertia
Does not depend on gravity
Same on earth and moon
Weight
A vector quantity that measures a body’s gravitational attraction to the earth
Fg= mg
Ac
V^2/r
Fc
Mv^2/r
Translational equilibrium
An object is in translational equilibrium when the sum of forces pushing it one direction is counterbalanced by the sum of forces acting in the opposite direction. It can be expressed as F=0
No net force= no acceleration = constant velocity not 0
Therefore in constant speed and direction
Equilibrium
No net force or net torque so NO acceleration- can be dynamic if at constant velocity or static is no velocity at all
When is the torque greatest
Force applied is 90 degrees or perpendicular to the lever arm
When is here no torque?
When sin is 0 because leave arm paralle to force
Torque positive
Counter click wise rotation
Torque negative
Clockwise rotation
Energy is measured
joules which is = Nm or kgm^2/s^2 and it is a scalar
Elastic Potential energy
U= 1/2kx^2
Mechanical Eeergy
E= U+ K
Sum of potential and kinetic energy
Work
Not energy, but a measure of energy transfer (other form of energy transfer is heat)
2 forms of energy ttransfer
Heat and Work
Conservation of energy
When there are no nonconservative forces (such as friction or air resistance) acting on a system, the total mechanical energy remains constant ( delta E= delta K+deltaU=0)
When is work possible
If F or a component of F is parallel to the displacement
When the piston expands work is done…
By the system and W>0
When the piston compresses the gas, work is done…
On the system and W<0
The area under the Pvs V curve is
The amount of work done in a system
Isovolumetric or isochoric Pressure
Constant V= no work is done
Isobaric Process
Constant P
Power
Rate at which work is done or rate of energy transfer
P= W/t or deltaE/t
Watts= J/s
Work unit
Joule= N*m
Machines provide mechanical advantage by?
Reduce force but do NOT change the amount of work done by increasing the distance:
Work-Energy Theorum
The total work done on any object is equal to the change in kinetic energy for that object
Mechanical Advantage compares values of
Forces (output force/input force)
efficiency compares values of
Work
Higher power means
It will reach any given velocity faster than one with a lowr power
