PHY1505_ Mock_ Exam 2020.

PHY1505_ Mock_ Exam 2020. Two objects are dropped from a bridge, an interval of 1.0 s apart, and experience no appreciable air resistance. As time progresses, the DIFFERENCE in their speeds. A. A. increases. B. Remains constant. C. C. decreases. D. D. increases at first, but then stays constant. E. E. decreases at first, but then stays constant. Answer Point Value: 4.0 points Answer Key: B As part of an exercise program, a woman walks south at a speed of 2.00 m/s for 60.0 minutes. She then turns around and walks north a distance 3000 m in 25.0 minutes. What is the woman's average velocity during her entire motion? A. 0.824 m/s south B. 1.93 m/s south C. 2.00 m/s south D. 1.79 m/s south E. 800 m/s south Answer Point Value: 4.0 points Answer Key: A The velocity of an object as a function of time is given by : v(t) = 2.00 m/s + (3.00 m/s) t - (1.0 m/s2 ) t2 . Determine the instantaneous acceleration of the object at time t = 4.00 s. A. - 2.00 m/s2 B. - 5.00 m/s2 C. 1.00 m/s2 D. 0.00 m/s2 E. -1.00 m/s2 Answer Point Value: 4.0 points Answer Key: B A car accelerates from 10,0 m/s to 30.0 m/s at a rate of 3.0m/s2 .How far does the car travel while accelerating? A. 80.0 m B. 133 m C. 226 m D. 399 m E. 320 m Answer Point Value: 4.0 points Answer Key: B A boy throws a rock with an initial velocity of at 30.0° above the horizontal. If air resistance is negligible, how long does it take for the rock to reach the maximum height of its trajectory? A. 0.110 s B. 0.194 C. 0.215 D. 0.303 s E. 0.310 s Answer Point Value: 4.0 points Answer Key: A A cart is moving with a constant horizontal velocity of 5.00 m/s. A small pebble is launched from the front of the cart with a velocity of 8.00 m/s at 60.0° above the horizontal as measured relative to the cart (see figure) and experiences no significant air resistance. Just as the pebble returns to the level from which it was launched, its distance from the front of the cart is closest to A. 2.83 m. B. 4.60 m. C. 5.66 m. D. 9.19 m. E. 11.3 m. Answer Point Value: 4.0 points Answer Key: C A stalled car is being pushed up a hill at constant velocity by three people. The net force on the car is A. zero B. up the hill and equal to the weight of the car C. Down the hill and equal to the weight of the car. D. Up the hill and greater than the weight of the car. E. Down the hill and greater than the weight of the car. Answer Point Value: 4.0 points Answer Key: A If a 5.0 kg box is pulled simultaneously by a 10.0 N force and a 5.0 N force, then its acceleration must be A. 3.0 m/s2 . B. 2.2 m/s2 C. 1.0 m/s2 D. 3.30 m/s2 E. We cannot tell from the information given. Answer Point Value: 4.0 points Answer Key: E The figure shows a graph of the acceleration of an object as a function of the net force acting on it. The mass of this object, in grams, is closest to A. 130 B. 11 C. 89 D. 8000 E. 120 Answer Point Value: 4.0 points Answer Key: A Two objects, each of weight W, hang vertically by spring scales as shown in the figure. The pulleys and the strings attached to the objects have negligible weight, and there is no appreciable friction in the pulleys. The reading in each scale.