Jeddah Knowledge International School Science Revision Pack Answer Key 2016-2017 Quarter 3 Grade 10 Name: Section: ANSWER KEY- SCIENCE GRADE 10, QUARTER 3 1
1. What are the units for mass? A Kilograms B Newtons C Newtons per kilogram D Metres 2. What is the formula for average speed? A Time taken distance moved B Distance moved time taken C Distance moved time taken D Distance moved time taken 3. What is on the vertical axis in a distance-time graph? A Distance travelled from the start B Time taken in seconds C Distance travelled in metres D Time from the start 4. What does a steep line correspond to in a distance-time graph? A No speed (stationary) B An accelerating speed C A fast steady speed D A slow acceleration 5. How is velocity different from speed? A B C Speed is velocity in a given direction Speed is always greater than velocity They are the same ANSWER KEY- SCIENCE GRADE 10, QUARTER 3
D Velocity is speed in a given direction 6. What is the formula for acceleration? A Change in velocity time taken B Time taken change in velocity C Change in velocity time taken D Speed x velocity 7. What is on the vertical axis in a speed-time graph? A Velocity of the object B Speed in metres per second C Distance travelled from the start D Acceleration in meters per second squared 8. What does a downwards line correspond to in a speed-time graph? A Constant acceleration B Constant deceleration C Returning to start D Distance to stop 9. What does the area beneath a velocity-time graph represent? A The average speed B The average velocity C The distance travelled D The time taken ANSWER KEY- SCIENCE GRADE 10, QUARTER 3 3
10. If a car increases in velocity from +5 m/s to +15 m/s in three seconds, what is its acceleration? A +33.3 m/s 2 B +3.3 m/s 2 C +10 m/s 2 D -33.3m/s 2 11. A car travels 300 m in 20 s, what is its average speed? 300 20 = 15 m/s 12. A woman runs after a bus. The bus is travelling at an average speed of 4 m/s. The woman runs 18 m in 6 s. Does she catch the bus? The woman s average speed is 18 6 = 3 m/s. So she will not catch a bus moving at 4 m/s. 13. A car accelerates in 5 s from 25 m/s to 35 m/s. Calculate its acceleration. Its velocity changes by 35-25 = 10 m/s. Therefore its acceleration is 10 5 = 2 m/s 2 14. A car decelerates in 5 s from 35 m/s to 25 m/s. Calculate its deceleration. Its velocity changes by 25-35 = -10 m/s. Therefore its acceleration is -10 5 = -2 m/s 2 Here is a velocity-time graph: The area under the line in a velocity-time graph represents the distance travelled. To find the distance travelled in the graph above, you need to find the area of the lightblue triangle and the dark-blue rectangle. ANSWER KEY- SCIENCE GRADE 10, QUARTER 3
15. Calculate the area of the light-blue triangle The width of the triangle is 4 seconds and the height is 8 metres per second. To find the area, you use the equation: Area of triangle = ½ base height So, the area of the light-blue triangle is ½ 8 4 = 16 m 2 16. Calculate the area of the dark-blue rectangle The width of the rectangle is 6 seconds and the height is 8 metres per second. So, the area is 8 6 = 48 m 2 17. Calculate the area under the whole graph The area of the light-blue triangle plus the area of the dark-blue rectangle is: 16 + 48 = 64 m 2 This is the total area under the distance-time graph. This area is the distance covered. 18. Arrange the following into the correct column: distance speed force time acceleration energy displacement velocity weight Scalar distance Speed time energy Vector weight acceleration velocity displacement force ANSWER KEY- SCIENCE GRADE 10, QUARTER 3 5
19. In the space below sketch the distance - time graph for an object that is stationary. 20. In the space below sketch the distance - time graph for an object with a constant velocity. ANSWER KEY- SCIENCE GRADE 10, QUARTER 3
21. A bicycle moving at 15m/s, if it takes 10 seconds to stop, what is its acceleration? Acceleration = Change in Velocity Time. a = ( v - u ) t a = acceleration v = final velocity (the one it ended up with) u = initial velocity (the one it started with) t = time v = 0 u = 15 t = 10 a = (0-15) 10 a = -15 10 a = -1 5 m/s 2 ANSWER KEY- SCIENCE GRADE 10, QUARTER 3 7