A car accelerates at a constant rate from zero to 36.8 m/s in 10 seconds and then slows to 13.9 m/s in 5 seconds. What is its average acceleration to the nearest tenth of a m/s2 during the 15 seconds?
Divide the velocity change (13.9 m/s) by the time interval (15 s). That will be the average acceleration.
0.93m/s^2
To find the average acceleration, we need to determine the change in velocity and the time interval. Here's how to calculate it step by step:
1. Determine the change in velocity during the first 10 seconds. From a starting velocity of 0 m/s, the car accelerates to a final velocity of 36.8 m/s. Therefore, the change in velocity is 36.8 m/s.
2. Determine the change in velocity during the next 5 seconds. From a velocity of 36.8 m/s, the car slows down to a final velocity of 13.9 m/s. Therefore, the change in velocity is 13.9 m/s.
3. Calculate the total change in velocity over the 15-second interval. Add the change in velocity during the first 10 seconds (36.8 m/s) to the change in velocity during the next 5 seconds (13.9 m/s). The total change in velocity is 36.8 m/s + 13.9 m/s = 50.7 m/s.
4. Calculate the average acceleration by dividing the total change in velocity by the total time interval. The total time interval is 15 seconds. Therefore, the average acceleration is 50.7 m/s / 15 s = 3.38 m/s^2.
Rounding to the nearest tenth, the average acceleration is approximately 3.4 m/s^2.