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Precalculus II
Technical Physics (Phy 111) Set 3 Test
Completely document your work and your reasoning.
You will be graded on your documentation, your reasoning, and the
correctness of your conclusions.
Date and Time are 02-15-2001 17:06:49
Signed by Learning Lab Attendant: ______________________
Date and Time: ______________________
Attendant:
Test is to be taken without reference to text or outside notes.
Calculator is allowed.
No time limit but test is to be taken in one sitting.
Please place test in Dave Smith's folder when completed.
Student:
Completely document your work.
Undocumented and unjustified answers may be counted wrong.
Besides undocument and unjustified answers, if wrong, never get partial credit.
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Problem Number 1
An object originally moving at a constant speed is acted upon for a specified time by a
constant force of 380 Newtons. At the end of the specified time the force is removed
and the object proceeds at a new constant velocity.
- If the object traveled a distance of 80 meters while under the influence
of the force, and if there was no dissipation of energy, then by how much would the
kinetic energy (abbreviated KE) of the object increase?
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Problem Number 2
An object of mass 13 kilograms is acted upon by a
net force of 1846 Newtons.
- The object is initially at rest.
- During the first 9 seconds, based on its velocity
change, by how much will its KE increase?
- During the first 9 seconds, based on the distance
it travels, how much work is done by the net force on the object?
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Problem Number 3
An object is being pushed by a force of 7 Newtons, directed parallel to its direction
of motion.
- We assume that the frictional and other dissipative forces are
negligible, so the object gains in energy all the work done by the force.
- How far will the object have to be pushed in order to gain 15 Joules of
energy?
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Problem Number 4
The kinetic energy of an object is equal to the
work required of the net force to accelerate it from rest to its present velocity.
It is easily enough shown that this work is equal to .5 m v^2, where m is the mass
and v the velocity of the object. This quantity is independent of the acceleration.
We therefore say that the kinetic energy of the object is .5 m v^2.
If an object of mass 70 kg is moving at 6
m/s, what is its KE?
- If its velocity doubles, what is its KE.
- By what factor does its KE increase when its
velocity doubles?
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Problem Number 5
If an object of mass 9.1 Kg and initially at rest is
pushed by a net force of 59.15 Newtons for 6.1 seconds, what are its acceleration, its final
velocity, its average velocity, and the distance it travels?