Precalculus II

Time and Date Stamps (logged): 17:12:20 06-10-2020 ｰｶ涓ｱ浤ｯｯｵ涓ｯ浤ｯｱｯ Precalculus II

General College Physics (Phy 201) Test 1

Completely document your work and your reasoning.

You will be graded on your documentation, your reasoning, and the correctness of your conclusions.

Test should be printed using Internet Explorer. If printed from different browser check to be sure test items have not been cut off. If items are cut off then print in Landscape Mode (choose File, Print, click on Properties and check the box next to Landscape, etc.).

Name and Signature of Student _____________________________

Signed by Attendant, with Current Date and Time: ______________________

If picture ID has been matched with student and name as given above, Attendant please sign here: _________

Instructions:

Test is to be taken without reference to text or outside notes.
Graphing Calculator is allowed, as is blank paper or testing center paper.
No time limit but test is to be taken in one sitting.
Please place completed test in Dave Smith's folder, OR mail to Dave Smith, Science and Engineering, Va. Highlands CC, Abingdon, Va., 24212-0828 OR email copy of document to dsmith@vhcc.edu, OR fax to 276-739-2590. Test must be returned by individual or agency supervising test. Test is not to be returned to student after it has been taken. Student may, if proctor deems it feasible, make and retain a copy of the test..

Directions for Student:

Completely document your work.
Numerical answers should be correct to 3 significant figures. You may round off given numerical information to a precision consistent with this standard.
Undocumented and unjustified answers may be counted wrong, and in the case of two-choice or limited-choice answers (e.g., true-false or yes-no) will be counted wrong. Undocumented and unjustified answers, if wrong, never get partial credit. So show your work and explain your reasoning.
Due to a scanner malfunction and other errors some test items may be hard to read, incomplete or even illegible. If this is judged by the instructor to be the case you will not be penalized for these items, but if you complete them and if they help your grade they will be counted. Therefore it is to your advantage to attempt to complete them, if necessary sensibly filling in any questionable parts.
Please write on one side of paper only, and staple test pages together.

Test Problems:

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Problem Number 1

A block of mass 8 kg on an incline angled at 36 degrees above the horizontal experiences a frictional force resisting its tendency to slide along the ramp. The upper limit on this frictional force is .19 of the normal force between the block and the ramp. What force must be exerted parallel to the ramp so that the block will slide at a uniform velocity down the ramp?

Problem Number 2

A cart of mass 1.3 kg coasts 60 cm up an incline at 5 degrees with horizontal. Assume that frictional and other nongravitational forces parallel to the incline are negligible.

What is the component of the cart's weight parallel to the incline?
How much work does this force do as the cart rolls up the incline?
How much work does the net force do as the cart rolls up the incline?
Using the definition of kinetic energy determine the velocity of the cart after coasting the 60 cm, assuming its initial velocity to be zero.

Problem Number 3

A ball of mass .4 kg is tossed vertically upward from altitude 8.7 meters and allowed to rise to a maximum altitude of 9.08 meters before falling to an altitude of 8.64 meters.

Determine the work done by gravity on the ball and the work done by the ball against gravity as it rises from its initial to its maximum altitude, and determine its kinetic energy change during that displacement.
Using energy considerations determine its initial velocity.
Determine the work done by gravity on the ball and the work done by the ball against gravity between its release at the 8.7 meter altitude and its final position at the 8.64 meter altitude.
Determine the change in kinetic energy between these positions, and use energy considerations to determine its velocity at the final position.
How are the work done by the ball and its kinetic energy change related?

Problem Number 4

Explain why the area under a position vs. time graph, between two clock times, is equal to the distance traveled between those two times.

Problem Number 5

Using the equations which govern uniformly accelerated motion determine vf, v0, a, Ds and Dt for an object which starts at velocity 10 cm /s and accelerates at .75 cm/s/s through a distance of 46 cm.

Reason out the quantities v0, vf, Dv, vAve, a, Ds and Dt: If an object’s velocity changes at a uniform rate from 10 cm/s to 13 cm/s as it travels 46 cm, then how long does it take to cover the distance?

Problem Number 6

Sketch a force diagram depicting weight and normal force for a glider gliding down an inclined air track. Indicate an x axis parallel to the incline and a y axis perpendicularto the x axis. Sketch the force vectors to scale and indicate their x and y components. Also sketch the net force vector, in the appropriate direction and also to scale.

We know that for an air cart gliding along an incline, the force that accelerates it is equal to W sin(`theta), where W is the weight of the cart and `theta the angle of the incline with horizontal.

If the force on the glider was W, what would be its acceleration?

If the acceleration of a mass is proportional to the net force acting on it, then

what should be the acceleration of the glider under the influence of a net force of .09 W?

what should be the acceleration of the glider under the influence of net force W sin(`theta)?

What should be the acceleration of the glider for `theta = 11 degrees?

What is the slope of the incline corresponding to this angle?

Explain why, for small angles, acceleration is proportional to slope.

Problem Number 7

A system consists of a cart pulled along a constant-velocity ramp by the force of gravity on a single paper clip, whose mass is much less than that of the cart, attached by a thread over a pulley with negligible friction. If the system accelerates at 3.7 cm/s², and if F = m a describes the relationship among net force F, mass m and acceleration a, give the acceleration of each of the following:

The same system but with 5 paper clips instead of one.

The same system but with a single paper clip and a cart of twice the mass.

The same system but with a single paper clip with a cart of half the mass.

The same system but with 10 paper clips and a cart of 15 times the mass.

What would be the acceleration of the same system but with a number of paper clips whose mass equals that of cart?

How would the slope of a graph of acceleration vs. number of paper clips for the original system (for a small number of paper clips) compare with the slope for a system with double the cart mass, and how would it compare with the slope of a system with 10 times the cart mass?