JR. GENIUS EDUCATIONAL SERVICES INC.

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1 1 Name: 1. Multiple Choice: 25 marks Copy to Scantron Card after finding the answer on the sheet. Fill in the Scantron card in the last 5 min. of the test. Do Short section first. 1. You are riding your bicycle northeast. If you decide to increase your velocity, in what direction is your acceleration? (a) southwest (b) north (c) east (d) northeast 2. A car slows down from 35.0 m/s [S] to 12.0 m/s [S] in 15.0 s. The displacement during this acceleration is (a) 6300 m (b) m (c) m (d) m 3. The slope of the following graph is as follows: 4. A steep slope on a distance-time graph indicates: (a) the object is not moving. (b) the object s speed is increasing. (c) the object has a low speed. (d) the object has a high speed. 5 A zero slope on a distance-time graph indicates: (a) the object is not moving. (b) the object s speed is increasing. (c) the object has a low speed. (d) the object has a high speed. 6. A long straight line on a distance-time graph indicates: (a) the object is changing speed. (b) the object is stopped. (c) the object maintained a uniform speed for a long period of time. (d) the object maintained a uniform speed for a short period of time. 7. The average speed of the following graph is as follows: (a) 2.5 m/s (b) 3 m/s (c) 1.0 m/s (d) 1.4 m/s

2 2 (a) 0.5 m/s (b) 2.0 m/s (c) 0.63 m/s (d) 0.56 m/s 8. Which of the following graphs does NOT represent an object travelling at a uniform speed? 9. Instantaneous speed and average speed are always the same when (a) the time period they are measured in is very great. (b) the distance travelled by the object undergoing instantaneous and average speed is the same. (c) the speed is uniform or constant. (d) the acceleration is changing per unit time An object covers less and less distance per unit time is an example of (a) constant speed (b) speeding up (c) instantaneous speed

3 (d) slowing down 11. A car covers more distance per unit of time is an example of (a) constant speed (b) speeding up (c) instantaneous speed (d) slowing down 12. A person walks across the classroom travelling equal distances in equal amounts of time. This is an example of (a) constant speed (b) speeding up (c) instantaneous speed (d) slowing down 13. Acceleration is defined as (a) change in position over a period of time; (b) change in speed over a period of time; (c) same position over a period of time; (d) the time it takes for an object to go from position 1 to position An example of constant non-zero acceleration is (a) a car travelling at the same speed per unit time; (b) a car stopped; (c) a car coming to a traffic light, stopping, and speeding up again; (d) a car speeding up the same amount per unit time A ball rolls down a ramp. As shown on the graph, what is the distance it covers? (a) 5.8 m (b) 5.0 m (c) 2.5 m (d) 2.9 m 16. A scalar quantity has all the following except (a) size (b) direction (c) unit (d) time

4 4 17. Which of the following is an example of velocity? (a) 40 km (b) 20 km/h[e] (c) 1.5 m [right] (d) 15 km/h 18 Which of the following graphs illustrates a accelerated positive speed for the whole trip? (a) A (b) B (c) C (d) D 19. Which of the following graphs illustrates an object travelling at a certain speed and then slowing down? 20 What is the instantaneous speed at 2.0 s? (a) A (b) B (c) C (d) D (a) 5 m/s (b) 10 m/s (c) 2.5 m/s (d) 2.5 m/s 2

5 21 Bob runs 5 km [W], 10 km [E] and then 15 km [W]. His resultant displacement is (a) +10 km (b) 30 km (c) 10 km (d) +15 km 22 The average velocity of the runner as shown in the graph: A snowball is thrown at 10.0 m [E] in 1.25 s. What velocity was the snowball thrown at? (a) 10.0 m/s [E] (b) m/s [E] (c) 12.5 m/s [E] (d) 8.00 m/s [E] 25. A blue jay flies at 10 km/h for 320 km [N]. How long would this journey take it? (a) 32 h (b) 3200 h (c) h (d) 3200 h [N] 5 (a) 10 m/s [N] (b) 0.29 m/s [S] (c) 0.29 m/s [N] (d) 10 m/s [S] 23 Two vectors are shown below. If these two vectors were added together which of the following would be the resultant vector? 24

6 6 2. Short - 40 marks- 30 min. 1. Classify each of the following as distance, displacement, speed or velocity by writing these words in the blanks at the right. /4 (a) Charlie walks 4.0 km west. (b) Bob runs around the neighbourhood at 3.0 km. (c) Sue rides her bike west at 15 m/s. (d) Doug walked his dog at 2 km/h last night. 2 Write a brief description about the motion of the following object and include the direction and relative size of the different velocities. /3 The object has stopped south of the school for several minutes and then proceeds north at a fast, constant velocity until it reaches the school. The object then goes south away from the school for a few minutes at a slower, constant velocity. 3. The graph below is a position-time graph for a ball rolling down a ramp. (a) What is happening to the velocity of the ball as it rolls down the ramp? How do you know this? /1 (b) What kind of motion does the position-time graph represent? /1 (c) What is the displacement of the ball after 1.5 seconds? /2 (d) What is the instantaneous velocity of the ball at 2.0 seconds?

7 7 /2 (e) What is the average velocity of the ball after 2.0 seconds? /1 (a) The velocity of the ball increases as it rolls down the ramp. The increasing slope of the graph indicates this increase in velocity. (b) The position-time graph represents accelerated motion. (c) The displacement of the ball after 1.5 seconds is 4 m. (d) slope = rise run = (14 0) m [down ramp] ( ) s = 7.0 m/s [down ramp] The instantaneous velocity of the ball at 2.0 seconds is 7.0 m/s [down ramp]. (e) The average velocity after 2.0 s is found by drawing a line from 0 s to 2.0 s and finding its slope. slope = rise run = (7 0) m [down ramp] ( ) s = 3.5 m/s [down ramp] The average velocity of the ball after 2.0 seconds is 3.5 m/s [down ramp]. /14 4 Describe the motion of the jogger on each section of the velocity-time graph. Be sure to specify the direction of the motion. /6 A B C D E F A- The jogger runs north at a constant velocity of 3.0 km/h for about 1.0 h. B- The jogger slows down from 3.0 km/h to 0 km/h in 1.0 h. C- The jogger remains stationary for another hour, no velocity. D- The jogger speeds up in the south direction from 0 km/h to 4 km/h for 1.0 h. E- The jogger remains stationary for another hour, no velocity. F- The jogger speeds up in the north direction from -4 km/h to 0 km/h for 1.0 h.

8 5. A water balloon is dropped from rest to the sidewalk below. It takes 15.0 seconds for the water balloon accelerating at 9.81 m/s 2 [down] to reach the sidewalk. Calculate the velocity of the water balloon as it hits the sidewalk. Draw a graph /5 v 1 = 0 m/s t = 15.0 s a = 9.81 m/s 2 [down] = m/s 2 v 2 =? v 2 = v 1 + a t = ( m/s 2 ) x 15.0 s = m/s or 147 m/s [down] The velocity of the water balloon as it hits the sidewalk is 147 m/s [down] 6. /3 Round the following values to a certainty of four significant digits. (a) (b) (c) The correct answers are (a) 47.89, (b) 1010, (c) / /4 Determine the number of significant digits for each of the following: (a) 5 scooters (b) (c) (d) 450 The correct answers are (a) infinite, (b) 5, (c) 2, and (d) A speed limit in a city or town, unless otherwise posted, is 50 km/h. Convert 50 km/h into metres per second. /2 v = 50 km x 1h x 1 min x 1000 m = 14 m h 60 min 60 s 1 km s

9 9 8. Barry travels 3 km [E] and then 4 km [S]. Draw a vector diagram to determine Barry s displacement. Do not forget to measure the angle for direction. /6 = 500 m [W] 350 s = 1.43 m/s [W] The velocity during the second part of his activity was 1.43 m/s [W]. Average velocity for whole activity r d R = +150 m m = -350 m or 350 m [W] t = 40 s s = 390 s r dr v av = t = 350 m [W] 390 s = m/s [W] The velocity during his whole activity was m/s [W].