A drag racer must accelerate from rest to a speed of 80 m/s. If the car accelerates uniformly at 4.0 m/s², what is the minimum track length required to reach this speed?
- 750 m
- 800 m
- 850 m
- 900 m
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A drag racer must accelerate from rest to a speed of 80 m/s. If the car accelerates uniformly at 4.0 m/s², what is the minimum track length required to reach this speed?
\(B\)
| \(v^2\) | \(=u^2 + 2as\) | |
| \(s\) | \(=\dfrac{v^2-u^2}{2a}\) | |
| \(=\dfrac{80^2-0^2}{2 \times 4}\) | ||
| \(=800\ \text{m}\) |
\(\Rightarrow B\)
A stone is tossed vertically upward from the edge of a canyon. It rises 9 meters above the rim before falling down to the canyon floor, which is 27 meters below the rim.
What is the total distance travelled by the stone?
\(C\)
\(\Rightarrow C\)
A bus departs from its depot, starting from rest and accelerating uniformly at 2.0 ms\(^{-2}\) for 10 seconds until it reaches a speed of 20 ms\(^{-1}\). It then travels at this constant speed for 50 seconds before decelerating uniformly at – 2.5 ms\(^{-2}\) until coming to a complete stop at the next bus stop. --- 6 WORK AREA LINES (style=blank) --- --- 4 WORK AREA LINES (style=lined) ---
Using the velocity-time graph below
Part 1
Determine the magnitude of the displacement:
Part 2
Determine the average acceleration between 4 and 8 seconds:
Part 1: \(C\)
Part 2: \(B\)
Part 1
\(\text{Area}\ =(4 \times 8) + (\dfrac{1}{2} \times 4 \times 8) = 32 +16 = 48\ \text{m}\)
\(\Rightarrow C\)
Part 2
\(a= \dfrac{\Delta v}{\Delta t} = \dfrac{0-8}{8-4} = -2\ \text{ms}^{-2}\)
\(\Rightarrow B\)