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The graph shows how the speed v of a car varies with time t - Scottish Highers Physics - Question 1 - 2019
Question 1
The graph shows how the speed v of a car varies with time t. The average speed of the car during the 12.0 s is A 1.25 m s⁻¹ B 2.08 m s⁻¹ C 2.50 m s⁻¹ D 7.50 m s⁻¹ E... show full transcript
Worked Solution & Example Answer:The graph shows how the speed v of a car varies with time t - Scottish Highers Physics - Question 1 - 2019
Step 1
Calculate the Average Speed
Answer
To find the average speed over the time interval from 0 to 12 seconds, we need to determine the total distance traveled by the car during this time.
From the graph:
- The speed changes from 0 m/s to 15 m/s between 0 s and 4 s.
- At 4 s, the speed becomes constant at 15 m/s until 12 s.
We can calculate the distance for each segment:
-
From 0 s to 4 s:
- Average speed = (0 m/s + 15 m/s) / 2 = 7.5 m/s
- Distance = speed × time = 7.5 m/s × 4 s = 30 m
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From 4 s to 12 s:
- Speed is constant at 15 m/s.
- Distance = speed × time = 15 m/s × (12 s - 4 s) = 15 m/s × 8 s = 120 m
Now, total distance traveled = 30 m + 120 m = 150 m.
Finally, we calculate the average speed: Average speed = Total distance / Total time = 150 m / 12 s = 12.5 m/s.