A car travels on a straight, level road.
(a) Starting from rest, the car is going 34 ft/s (23 mi/h) at the end of 5.5 s. What is the car's average acceleration in ft/s2?
magnitude
Correct: Your answer is correct.
ft/s2
direction
Correct: Your answer is correct.
(b) In 4.5 more seconds, the car is going 68 ft/s (46 mi/h). What is the car's average acceleration for this time period?
magnitude
Correct: Your answer is correct.
ft/s2
direction
Correct: Your answer is correct.
(c) The car then slows to 51 ft/s (35 mi/h) in 3.5 s. What is the average acceleration for this time period?
magnitude
Correct: Your answer is correct.
ft/s2
direction
Correct: Your answer is correct.
(d) What is the overall average acceleration for the total time?
To find the overall average acceleration, we need to consider the total change in velocity and the total time.
First, let's find the total change in velocity:
Change in velocity = final velocity - initial velocity
For part (a), the initial velocity was 0 ft/s and the final velocity was 34 ft/s. So, the change in velocity for part (a) is 34 ft/s - 0 ft/s = 34 ft/s.
For part (b), the initial velocity was 34 ft/s and the final velocity was 68 ft/s. So, the change in velocity for part (b) is 68 ft/s - 34 ft/s = 34 ft/s.
For part (c), the initial velocity was 68 ft/s and the final velocity was 51 ft/s. So, the change in velocity for part (c) is 51 ft/s - 68 ft/s = -17 ft/s (negative because the car is slowing down).
Now, let's find the total time:
Total time = time for part (a) + time for part (b) + time for part (c)
Total time = 5.5 s + 4.5 s + 3.5 s = 13.5 s
Finally, let's calculate the overall average acceleration:
Overall average acceleration = (total change in velocity) / (total time)
Overall average acceleration = (34 ft/s + 34 ft/s - 17 ft/s) / 13.5 s
Overall average acceleration = 51 ft/s / 13.5 s
Overall average acceleration ≈ 3.78 ft/s²
Therefore, the overall average acceleration for the total time is approximately 3.78 ft/s².