Phys1111sampletest 3summer 2016 PDF

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Sample test 3 PHYS 1111

1) Person X pushes twice as hard against a stationary brick wall as person Y. Which one of the following statements is correct? A) Both do the same amount of positive work. B) Both do positive work, but person X does twice the work of person Y. C) Both do zero work. D) Both do positive work, but person X does four times the work of person Y. E) Both do positive work, but person X does one- half the work of person Y. 2) If the force on an object is in the negative direction, the work it does on the object must be A) positive. B) negative. C) The work could be either positive or negative, depending on the direction the object moves. 3) You and your friend, who weighs the same as you, want to go to the top of the Eiffel Tower. Your friend takes the elevator straight up. You decide to walk up the spiral stairway, taking longer to do so. Compare the gravitational potential energy of you and your friend, after you both reach the top. A) Your gravitational potential energy is greater than that of your friend, because you traveled a greater distance in getting to the top. B) Your friend's gravitational potential energy is greater than yours, because he got to the top faster. C) Both of you have the same amount of gravitational potential energy at the top. D) It is impossible to tell, since the distances you both traveled are unknown. E) It is impossible to tell, since the times you both took are unknown. 4) A child does 350 J of work while pulling a box from the ground up to his tree house at a steady speed with a light rope. The tree house is 4.0 m above the ground. What is the mass of the box? A) 8.0 kg B) 8.9 kg C) 5.3 kg D) 6.7 kg 5) A traveler pulls on a suitcase strap at an angle 36° above the horizontal. If 555 J of work are done by the strap while moving the suitcase a horizontal distance of 15 m, what is the tension in the strap? A) 37 N B) 56 N C) 52 N D) 46 N 6) How much work must be done by frictional forces in slowing a 1000- kg car from 26.1 m/s to rest? A) 4.09 × 105 J B) 2.73 × 105 J C) 4.77 × 105 J D) 3.41 × 105 J 7) A sled having a certain initial speed on a horizontal surface comes to rest after traveling 10 m. If the coefficient of kinetic friction between the object and the surface is 0.20, what was the initial speed of the object? A) 7.2 m/s B) 6.3 m/s C) 9.8 m/s D) 8.9 m/s E) 3.6 m/s 8) The figure shows a famous roller coaster ride. You can ignore friction. If the roller coaster leaves point Q from rest, what is its speed at the top of the 25- m peak (point S)?

A) 22 m/s

B) 62 m/s

C) 44 m/s

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D) 10 m/s

E) 120 m/s

9) As shown in the figure, a 4.0- kg block is moving at 5.0 m/s along a horizontal frictionless surface toward an ideal spring that is attached to a wall. After the block collides with the spring, the spring is compressed a maximum distance of 0.68 m. What is the speed of the block when the spring is compressed to only one- half of the maximum distance?

10) During World War I, Germany used a "Big Bertha" cannon to hurl shells into Paris 30 miles away. This gun also had a very long barrel. What was the reason for using a long barrel in these guns? A) to allow the force of the expanding gases from the gunpowder to act for a longer time B) to increase the force exerted on the bullet due to the expanding gases from the gunpowder C) to reduce frictional losses D) to reduce the force exerted on the bullet due to the expanding gases from the gunpowder E) to exert a larger force on the shells 11) A 0.14- kg baseball is dropped from rest from a height of 2.0 m above the ground. What is the magnitude of its momentum just before it hits the ground if we neglect air resistance? A) 0.62 kg · m/s B) 0.28 kg · m/s C) 0.44 kg · m/s D) 1.4 kg · m/s E) 0.88 kg · m/s 12) Two air track carts move along an air track towards each other. Cart A has a mass of 450 g and moves toward the right with a speed of 0.850 m/s. Cart B has a mass of 300 g and moves toward the left with a speed of 1.12 m/s. What is the total momentum of the two- cart system? A) 0.750 kg · m/s toward the right B) 0.719 kg · m/s toward the left C) 0.719 kg · m/s toward the right D) 0.047 kg · m/s toward the right E) 0.750 kg · m/s toward the left 13) A 328- kg car moving at 19.1 m/s in the +x direction hits from behind a second car moving at 13.0 m/s in the same direction. If the second car has a mass of 790 kg and a speed of 15.1 m/s right after the collision, what is th velocity of the first car after this sudden collision? A) 18.2 m/s B) - 14.0 m/s C) 24.2 m/s D) 14.0 m/s 14) A 1200- kg ore cart is rolling at 10.8 m/s across a flat friction - free surface. A crane suddenly drops 858 kg of ore vertically into the cart. How fast does the cart move just after being loaded with the ore? A) 5.70 m/s B) 6.30 m/s C) 4.20 m/s D) 3.80 m/s 15) Astronaut Jennifer's lifeline to her spaceship comes loose and she finds herself stranded, "floating" 100 m from the mothership. She suddenly throws her 2.00- kg wrench at 20 m/s in a direction away from the ship. If she an her spacesuit have a combined mass of 200 kg, how long does it take her to coast back to her spaceship? A) 250 s B) 1000 s C) 500 s D) 750 s E) 2.50 min

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