Final answer:
To find the acceleration, the change in velocity is divided by the time taken. With an initial velocity of 2.23 m/s and a final velocity of 3.13 m/s over a time of 0.17 seconds, the acceleration is calculated to be 5.29 m/s².
Step-by-step explanation:
To calculate the acceleration of the car when two washers are added to the string, you can use the kinematic equations for uniformly accelerated motion. Given the time to travel certain distances and the initial and final velocities, we can use the equation a = (v - u) / t, where v is the final velocity, u is the initial velocity, and t is the time taken. Since the times taken to travel 0.25 meters and 0.50 meters are provided, we can calculate the average speed during these intervals and then determine the acceleration using the change in speed over time.
In this case, we are given that the initial velocity u is 2.23 m/s and the final velocity v is 3.13 m/s. The change in velocity is therefore v - u = 3.13 m/s - 2.23 m/s = 0.90 m/s. The time interval given is from when the car is observed at 0.25 meters to when it's observed again at 0.50 meters, which is 0.28 seconds - 0.11 seconds = 0.17 seconds. The acceleration can then be calculated as a = 0.90 m/s / 0.17 s = 5.29 m/s².