Practice MT

11/16/22, 7:27 PM Quiz: Practice midterm Practice midterm Started: Nov 16 at 6:58p.m. Quiz Instructions The midterm covers all content up to and including Chapter 9 (week 9). The midterm will be in-person on Thursday Nov 17, 18:00-19:30 (rooms to be announced). The points will be distributed approximately half and half between short-answer/multiple-choice and problems with written solutions. > | Question 1 1 pts A t-shirt is drying by hanging from a clothesline as shown. If the tension in the clothesline is 11.2 N and it sags 15° below the horizontal, what is the mass of the t-shirt (plus hanger)? (Assume that the mass of the clothesline is negligible.) — S Give your answer in kg to three significant figures (without units). 0.592 [ > Question 2 1 pts At the airport, you attempt to run the wrong way along a moving walkway, which is moving towards you at -1.3 m/s. Your initial velocity when you enter the walkway is 2.0 m/s (relative to an observer on the ground) and you speed up with a constant acceleration of 0.1m/s?. If it takes you 13.9s to get to the far end of the walkway, how long is it? Give your answer in m to three significant figures (without units). 19.4 [ | Question 3 1pts A car of mass 1,081 kg traveling north (+y-direction) at 30 km/h is entering an intersection when it collides with another car 1,147 kg that is traveling east (+x-direction) at 40 km/h. The cars stick together on impact. Assume that it's winter and the intersection IS so slippery that we can neglect friction. Calculate their final speed immediately after the collision. Give your answer in km/h to three significant figures (without units). 25.2 https://canvas.ubc.ca/courses/104267/quizzes/555096/take 1/7

11/16/22, 7:27 PM Quiz: Practice midterm Question 4 1 pts Three masses are arranged as shown over a light (massless) pulley and the system is released. What is the acceleration of the system? » O 1/2¢ O 134g O 14g O 1/5¢g O 213 ¢ O 2/5¢g O 34 g @ 3/5¢ Question 5 1 pts Consider the following three cases of a box on an inclined plane. The only difference between the three cases is in an additional external force that pushes on the boxes in two cases, in the directions shown (green arrows). In each case, the box remains at rest so static friction keeps it in place. Rank the magnitude of the static friction forces. Assume that 6 = 15° and that the coefficient of static friction is s = 0.45. [ans] Question 6 1 pts Assume the acceleration of an object (in m/s?) is given by a(t) = —4.5t + ag where ag=17.6 m/s? is the acceleration at t = 0s. Assuming that the initial velocity of the object is vg = 9.2 m/s, at what time does the object change direction? Give your answer in seconds to three significant figures (without units). https://canvas.ubc.ca/courses/104267/quizzes/555096/take 27

11/16/22, 7:27 PM Quiz: Practice midterm i g 5_. 4— 509 1 1509 | @i% ——{g0g +— y AR EEENE Y 0 24 5 5 10 Give your answer (in units of the grid) to three significant figures. 5.422 [ > Question 10 0.5 pts What is the y-position of the center of mass of this toy truck consisting of six parts: four solid disks (wheels), one solid rectangular block, one solid cube. (Two of the wheels are not shown. ) i .6._..1 4 509 2 — _ 150g « @i} : (E30ga—— ; WNEERENEE ; g oo Bt Give your answer (in units of the grid) to three significant figures. 1.9375 > | Question 11 1 pts Two balls strike each other in a nearly head-on collision. The figure below shows the momentum of Ball 1 (p4,j) and the momentum of Ball 2 (p» ;) before the collision, and the momentum of Ball 1 (p4 ) after the collision. There are no forces acting on the balls, except the collision forces. https://canvas.ubc.ca/courses/104267/quizzes/555096/take 4/7

11/16/22, 7:27 PM Quiz: Practice midterm b If the magnitude of vector p1 j is 26.2kg m/s, what is the magnitude of the final momentum of ball 2 (p5 )7 Give your answer in kg m/s to three significant figures (without units). 37.05 Question 12 1 pts 0 Consider the case of a ball rolling up the ramp, then back down. Which is the correct acceleration graph? a, a a a, a, O A @ B OC OD OE Question 13 1 pts A car is rolling through a valley without using its engine. There is a bit of air drag acting on the car, but rolling friction is negligible. Which is the correct free-body diagram for the forces acting on the car at the bottom of the valley (point shown in the picture)? https://canvas.ubc.ca/courses/104267/quizzes/555096/take 5/7

11/16/22, 7:27 PM 0.2857 Quiz: Practice midterm Quiz saved at 7:27pm Submit Quiz https://canvas.ubc.ca/courses/104267/quizzes/555096/take 717