General Physics Exam 1 Practice

𝑅= 𝑣𝑜2 sin 2𝜃 𝑔 Questions 1 - 3 will refer to the position vs. time diagram to the left. Assume it is for a dog running in a field to catch a ball. 1. What is the displacement of the dog after 10 s? A) 30 m B) 10 m C) 0 m D) 6 m E) 60 m 2. What is the velocity of the dog at 25 s? A) 20 m/s B) 2 m/s C) 4 m/s D) -2 m/s E) -4 m/s 3. When is the acceleration of the dog positive? A) at 5 s B) at 10 s C) at 20 s D) at 30 s E) at 40 s 2 4. Which of the position vs. time plots below show positive acceleration? A) 4 only B) 5 only C) 2, 5 and 6 D) 6, 7 and 8 E) 3, 4 and 7 5. A train has been moving forward with constant velocity. Now, it begins to slow and then come to a stop at the station, where it opens its doors. Which of the following is the most correct statement about what happened? (Assume a coordinate system where forward is positive and backward is negative.) A) The train had negative velocity and then experienced negative acceleration. B) The train had negative velocity and then experienced positive acceleration. C) The train had positive velocity and then experienced negative acceleration. D) The train had positive velocity and then experienced positive acceleration. E) The train experienced negative acceleration only. 3 6. A mother is backing up her car quickly to go to work. As she is backing up, she hears a dog bark from behind her, and she slams on the brakes. Which of the following is the most correct statement about what happened? (Assume a coordinate system where forward is positive and backward is negative.) A) The car had negative velocity and then experienced positive acceleration. B) The car had negative velocity and then experienced negative acceleration. C) The car had positive velocity and then experienced positive acceleration. D) The car had positive velocity and then experienced negative acceleration. E) The car experienced positive acceleration only. 7. A cyclist starts a timed race at 6.0 mi/hr. In order to win, he must average 21 mi/hr. Assuming constant acceleration from the start, how fast must he be traveling at the end of the race? A) 30 mi/hr B) 36 mi/hr C) 24 mi/hr D) 42 mi/hr E) 40 mi/hr 8. Human reaction times are worsened by alcohol. How much farther would a drunk driver’s car travel before he hits the brakes than a sober driver’s car? Assume both cars are initially traveling at 49.0 mi/hr, the sober driver takes 0.33 s and the drunk driver takes 1.0 s to hit the brakes. Also, 1 mile = 5280 ft, 1 hr = 3600 s. A) 58 ft B) 34 ft C) 53 ft D) 48 ft E) 109 ft 4 9. A rock is dropped from rest into a pit and accelerates due to gravity at 9.8 m/s2. It hits the ground in 5 seconds. A second rock is then dropped from rest into another pit, and hits the ground in 10 seconds. How much deeper is the second pit, compared to the first pit? A) one and a half times deeper B) two times deeper C) three times deeper D) four times deeper E) six times deeper   10. The components of two vectors B and C are: Bx = -9.2 Cx = -4.5 By = -6.1 Cy = 4.3   The angle (less than 180 degrees) between vectors B and C is closest to: A) 77 B) 103 C) 10 D) 170 E) 84 11. You walk 53 m to the north, then turn 60° to your right and walk another 45 m. Determine the direction of your displacement vector. Express your answer as an angle relative to east. A) 50° north of east B) 63° north of east C) 57° north of east D) 69° north of east E) 43° north of east 5 12. A tennis ball is thrown vertically upwards, reaches a highest point, and returns to the ground. When the ball is at the top of its path, its acceleration A) is zero. B) is directed upwards. C) is directed downwards. D) changes direction from upwards to downwards. E) could be either upwards or downwards, depending on the initial velocity. 13. An airplane has a speed in still air of 300 km/hr, and sets out on a course that is 30° north of east (see below). The wind velocity with respect to the ground is 60 km/hr from the east. What is the airplane’s velocity with respect to the ground? A) 360 km/hr, 31° north of east B) 240 km/hr, 45° north of east C) 250 km/hr, 37° north of east D) 270 km/hr, 33° north of east E) 220 km/hr, 40° north of east 6 Questions 14 – 20 refer to the figure at left. This is a screenshot from the PhET website that we used in lecture. The cannonball is shot with an initial velocity of 18.0 m/s, at an angle of 64° from the horizontal. Assume that gravity accelerates the cannonball downward at 9.80 m/s2, and that there is no air resistance. 14. What is the initial velocity of the cannonball in the y-direction? A) 7.8 m/s B) 16.2 m/s C) 15.6 m/s D) 18.0 m/s E) 10.3 m/s 15. What is the initial velocity of the cannonball in the x-direction? A) 10.3 m/s B) 7.9 m/s C) 16.2 m/s D) 18.0 m/s E) 15.6 m/s 16. How long does it take for the cannonball to reach the top of its flight? A) 3.31 s B) 0.40 s C) 1.84 s D) 0.80 s E) 1.65 s 7 17. Assume that the total time in the air is just twice the time it takes to get to the top of its flight. Now, what will be the total horizontal distance travelled by the cannonball? A) 6.2 m B) 33.9 m C) 26.9 m D) 25.7 m E) 53.5 m 18. What is the maximum height attained by the cannonball? A) 3.2 m B) 17.6 m C) 27.8 m D) 13.4 m E) 10.0 m 19. What is the magnitude and direction for the velocity vector of the cannonball at t = 1.2 s? A) 8.3 m/s, 0° above the horizontal B) 9.0 m/s, 30° above the horizontal C) 9.7 m/s, 47° above the horizontal D) 8.7 m/s, 5° below the horizontal E) 16.2 m/s, 38° above the horizontal 20. At what time is the velocity of the cannonball 11.0 m/s, 45° below the horizontal? A) 2.4 s B) 1.8 s C) 2.1 s D) 1.7 s E) 2.6 s 8