Work/Power
Equation for Work
F x d
A ramp and stairs are examples of this type of machine.
Inclined Plane
Can energy be created or destroyed?
No
Equation for GPE
mgh
what does kinetic mean?
moving/in motion
Equation for Power
W/t
Equation for mechanical advantage.
F-out/F-in
Equation for conservation of energy.
MA=KE+PE
or
KE=PE
variable used for potential energy
U
Equation for kinetic energy
1/2mv2
Unit for Power
Watt
Ideal mechanical advantage uses ________ instead of force.
distance/displacement
T or F
A greater height for GPE translates to greater velocity for KE.
True
Equation for elastic potential energy
1/2kx2
If the speed of an object doubles, how does its kinetic energy change?
4x
Work done equals change in _________
Energy
What is the efficiency of a machine that uses 20 joules of work to produce 17 joules of work?
85%
How much kinetic energy does a 30kg object have when sitting at 6m off the ground?
30 x 9.8 x 6 = 1764 J
MY MISTAKE
0 KE or 1764 J GPE
what type of energy is in springs and rubber bands
elastic potential energy
a roller coaster will have the most kinetic energy where?
bottom of tallest hill
How much work is done by pushing a 40N crate a distance of 10m? (Must use correct unit.)
400 Joules
T or F
A machine can multiply work.
False
What is the velocity of a 500kg roller coaster at the bottom of a 100m drop?
PE = 500 x 9.8 x 100 = 490000 J
490000 J = 1/2 x 500 x v2
490000/250 = v2 =1960
v = 44 m/s
an object at 100m from the ground will have MORE or LESS GPE than one at 50m from the ground?
MORE
How much kinetic energy would a 2000kg car have while traveling 10m/s?
100,000 J