# Sample2 MT2 - 1) A box of mass 100 kg is pulled across the...

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1) A box of mass 100 kg is pulled across the floor at a constant velocity by a horizontal rope attached to box, as shown in the figure. The tension in the rope is 10 N. The work done by the tension in the rope in moving the box 5 m is: T=10N A) 2 J B) 20 J C) 50 J D) 500 J E) 1000 J 2) A 100 kg skier starts from rest at the top of a ski slope that is 50 m long. If her final speed at the bottom of the slope is 4 m/s, where the bottom of the slope is 20 m below the top (see diagram below) what is the average force of friction between the skis and the slope? A) 16 N B) 199 N C) 376 N D) 392 N E) 408 N Page 1

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3) A pick-up truck is transporting a stack of 5 plywood sheets, each of mass 10 kg. The coefficient of static friction between any two sheets is 0.7, and that between the bottom sheet and the bed of the pick-up truck (which is rubberized) is 0.9. The truck is traveling horizontally at constant speed, when the driver needs to hit the brakes suddenly to avoid hitting a deer crossing the road. The truck decelerates at a rate of -5 m/s 2 , and the plywood sheets are unsecured (not strapped down). Which, if any, sheets will slide forward relative to the truck during the braking? A) The top sheet only will slide forward. B) The top 3 sheets will slide forward. C) The top 4 sheets will slide forward. D) All of them will slide forward. E) None of them will slide forward. 4) At what maximum speed can a car round an unbanked circular curve (flat road) with a radius of 50 m without slipping sideways? Assume that the road is dry, so that the coefficients of friction between the tires and the road are 0.8 for kinetic friction and 1.0 for static friction. A) 19.8 m/s B) 22.1 m/s C) 35.3 m/s D) 50.2 m/s E) 62.3 m/s Page 2
5) A pig is given a quick push up a ramp angled at 30° to the horizontal, and let go with an initial speed of 4 m/s. The pig slides up the ramp with a coefficient of kinetic friction of 0.3 until it comes to a halt. What total distance along the slide does the pig travel before it stops? μ k = 0.3 v 0 = 4 m/s θ =30 ° A) 1.63 m B) 0.803 m C) 1.07 m D) 2.08 m E) 3.14 m 6) A Physics 211 student watches a maple leaf gently fall from a tree on a calm autumn day. At the time she notices the leaf, it is falling at constant speed until it hits the ground. She draws the following conclusions for the motion observed. Which, if any, are correct ? i) The net force on the leaf is zero. ii) The work done by air resistance has the same magnitude as the work done by gravity. iii) The mechanical energy K+U is conserved during the fall of the leaf. iv) The work done by air resistance on the leaf is negative. A) ii), iii) and iv) only B) i) and ii) only C) i) and iv) only D) i), ii) and iv) only E) all four statements are true Page 3

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7) Spiderman swings around a construction crane, with his spider thread stretched taut at a length R. He makes a full vertical rotation around the crane, but at the top barely loops the loop at speed V t , i.e., the tension in his thread is momentarily zero there.
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## This note was uploaded on 12/28/2010 for the course PHYS 211 taught by Professor Staff during the Fall '08 term at Pennsylvania State University, University Park.

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Sample2 MT2 - 1) A box of mass 100 kg is pulled across the...

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