A car slows down from 23 m/s to rest in a distance of 85m. What is its constant acceleration?
I got -6.224, but a friend was telling me it's -3.11 and that I had to divide by 2. Why is that?
The average velocity during deceleration is 11.5 m/s. The time required to decelerate is 85/11.5 = 7.39 s
The acceleration rate is -23 m/s/7.39s = -3.11 m/s^2
I added the minus sign because it is decelerating
How did you get the average velocity?
i think -3.11
A car slows down uniformly from a speed of 15.0 m/s to rest in 6.00 s .
To find the constant acceleration of the car, you can use the kinematic equation:
Vf^2 = Vi^2 + 2ad
Where:
Vf = final velocity (0 m/s, as the car comes to rest)
Vi = initial velocity (23 m/s)
a = acceleration (unknown)
d = distance traveled (85 m)
Since the car slows down, the acceleration will be negative. Rearranging the equation and plugging in the given values:
a = (Vf^2 - Vi^2) / (2d)
a = (0^2 - 23^2) / (2 * 85)
Evaluating the expression results in:
a = (-529) / 170
a ≈ -3.112
Therefore, the correct answer is -3.112 m/s². The value should be negative because the car is slowing down.
It seems your friend mentioned dividing by 2. This might be a result of a common mistake made when using the equation incorrectly. It's important to note that dividing by 2 is unnecessary in this case since there is no specific condition that requires dividing by 2 in the equation mentioned.