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Newtons Laws (Force, Mass, Motion)
Simple Machines
Elements, Compounds, Mixtures
Work and Power
Waves
100
What is Newtons First law of motion?!
. Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.
100
What is a lever?
A rigid bar resting on a pivot, used to help move a heavy or firmly fixed load with one end when pressure is applied to the other.
100
What is an element?
an element is, a pure substance that CAN NOT BE BROKEN DOWN; into simpler substances.
100
What is the SI Unit for work? a. watt b. ampere c. newton d. joule
The correct answer is d
100
What is the spectrum?
is a condition that is not limited to a specific set of values but can vary infinitely within a continuum.
200
What does the law of universal gravitation state?
All objects are attracted to each other by a gravitational force
200
What affects the mechanical efficiency of compound machines?
With each simple machine, the mechanical efficiency decreases. Ex. Efficiency of a can opener : 95% x 90% x 80% = 68%
200
What is a compound? (HINT):examples of a compound are water and/or carbon dioxide
a compound is made up of two or more types of elements; that are "CHEMICALLY" combined.
200
Which is a third class lever? a. a hammer b. a broom c. a wheelbarrow d. a nutcracker
The answer is b. The brooms input force is between the fulcrum and the output force. A hammer is a first class lever. A nutcracker and a wheelbarrow are second class levers
200
What are light waves?
refers to electromagnetic radiation of any wavelength, whether visible or not OR electromagnetic radiation, particularly radiation of a wavelength that is visible to the human eye.
300
What is the acceleration due to gravity?
9.88 m/s^2
300
If an inclined plane has a height of 3 meters and a length of 10 meters, what is the mechanical advantage?
Mechanical advantage = Length / Height MA = 10 m / 3 m MA = 3.33
300
What is a mixture?
a mixture is a substance made by mixing other substances; and they are combined together.
300
Does a weight lifter transfer more NRG, less NRG, or the same amount of NRG when lifting the weight faster?
The weight lifter would transfer the same amount of NRG regardless of how fast the weight is lifted because the work does not change. Remember that work is dependent on force and distance
300
What are sound waves?
A wave of compression and rarefaction, by which sound is propagated in an elastic medium such as air.
400
A 3000 N force acts on a 200 kg object. What is the acceleration of the object?
F=m x a a=F/m a=3000 N / 200 kg a=15 m/s^2
400
What is the mechanical advantage of a movable pulley?
MA=1
400
How are elements, compounds, and mixtures related to one another?
They all are made up compounds. They all require mass; which takes up space. They all are made up of elements.
400
How much time is needed to produce 720 J of work if 90 watts of power is used?
Power=Work/Time Time=Work/Power *Watts = 1 J/s T=720 J / 90 W T=8 s
400
What are compressional waves?
a shock wave that compresses the medium through which it is transmitted.
500
A 82 kg sprinter accelerates from the starting blocks to 11.2 m/s in 60 meters. Assuming no friction how much force does the sprinter generate?
S=d/t t=d/s t=60 m / 11.2 m/s t=5.4s a=(vf-vi)/t a=(11.2 m/s - 0 m/s) / 5.4 s a=(11.2 m/s) / 5.4s a=2.1 m/s^2 F= m x a F= 82 kg x 2.1 m/s^2 F= 172.2 N
500
If the input arm of a lever is 5 meters and the output arm of a lever is 10 meters, what is the mechanical advantage? Which class of lever is this?
Mechanical Advantage = Length of input / Length of output MA = 5 m/10 m MA = 0.5 If the input arm is shorter than the output, it is a 3rd class
500
What of the following are examples of a mixture? a.milk b.cheese c.wheat thins d.carbonated soda
The answer is a. and d. because they both include substances made up of other substances.
500
A new conveyor system at the local packaging plan will utilize a motor-powered mechanical arm to exert an average force of 890 N to push large crates a distance of 12 meters in 22 seconds. Determine the power output required of such a motor.
W=(Force)(Distamce) W=(890 N)(12 m) = 10680 J P=Work/Time P=10680 J / 22 s = 485.5 J/s
500
What are compressional waves, also refered to as?
"LONGITUDINAL WAVES"