Work
What is the correct definition of work?
What happens when an object changes its position by moving in the direction the force is being applied
Power is the measure of _________ at which you do work
rate, or how fast
Kinetic Energy is _______ energy where as potential energy is known as ___________.
moving, stored
What is the definition of Mechanical Advantage?
The number of times a machine multiplies the effort force.
What class lever has the effort in the middle?
FRE
123
3RD CLASS LEVER
Which formula gives you the measure of how much work has been done?
work = force X distance
Power is measured in
Watts
The law of conservation of energy states...
Energy can neither be created nor destroyed
What is the correct formula for Mechanical Advantage?
MA= Effort arm/resistance arm
An axe head splitting a log is what type of simple machine?
a wege (2 inclined planes)
The correct unit for work is
joules
How much power would it take to move a chair 5 meters in 15 seconds using a force of 51 newtons?
First, find work: 51 x 5 = 255
Power = work/time 255/15= 17 W
Which formula expresses the work output, or the amount of work actually done by the machine
Fr x dr
To increase the mechanical advantage of a lever, you move the fulcrum closer to the _____________ and farther from the _______________.
load (resistance) , effort
What type of simple machine can we find on a car?
Wheel and axle
15 Joules
A 600 newton diver dives off a 10-meter platform. if it takes him 2 seconds to hi the water, what is his power?
First find work. F x D= 600x 10 = 6,000
Power = W/T 6,000/2 = 3,000 watts
the 6 forms of energy include..
Chemical
radiant
heat
nuclear
mechanical
electrical
What is the mechanical advantage of a simple machine if a force of 15 newtons lifts an object weighing 45 newtons?
MA Effort arm/resistance arm
45 = Effort
15 = resistance
45/15= 3
Screws and wedges are variations of what simple machine?
An incline plane
A landscaper attempted to move a 300kg boulder for 30 minutes but could not budge it. How much work did the worker do?
No work, as he did not move the boulder.
Abbey pushed a stroller 2 blocks in 3 minutes. Then she pushed it 2 more blocks in 2 minutes. When did she use more power?
When she pushed it 2 blocks in 2 minutes. It took less time meaning she needed to use more power to get the job done.
A person uses a lever to lift a loaded shipping carton. The person applies 150 newtons of effort force and pushes the end of the lever 0.75 meters. The lever exerts 250 newtons of resistance force.It lifts the carton 0.4 meter.
What is work input?
What is work output?
What is the efficiency of the lever?
Input = Fe x de
150 x 0.75 =112.5
Output = Fr x dr
250 x 0.4 = 100
Efficiency= output/input x 100%
100/112.5= 0.88 x 100= 88.8
In a lever, the effort arm is 60 cm long and the resistance arm is 20 cm long. What is the mechanical advantage?
MA = Effort arm/ resistance arm
MA= 60/20= 3
What do you need for any simple machine to do work?
Energy