A car is initailly travelling at 50.0km/h. The brakes are applied and the car stops over a 35m distance. What was magnitude of the car's acceleraion while it was braking?

I don't know what formula to use.

V^2 = Vo^2 + 2a*d

V = 0
Vo = 50km/h = 50000m/3600s = 13.89 m/s
d = 35 m.
Solve for a. It will be negative.

To find the magnitude of the car's acceleration while braking, you can use the following formula:

a = (v^2 - u^2) / (2 * s)

Where:
a = acceleration (magnitude)
v = final velocity (0 m/s since the car stops)
u = initial velocity (50.0 km/h = 13.9 m/s)
s = distance traveled (35 m)

First, convert the initial velocity from km/h to m/s:
u = 50.0 km/h * (1000 m / 1 km) * (1 h / 3600 s)
u = 13.9 m/s

Now, substitute the values into the formula:

a = (0^2 - 13.9^2) / (2 * 35)
a = (-193.21) / 70
a ≈ -2.76 m/s²

Therefore, the magnitude of the car's acceleration while braking is approximately 2.76 m/s² in the negative direction.

To calculate the magnitude of the car's acceleration while braking, you can use the following formula:

acceleration = change in velocity / time

However, in this case, we are not directly given the time it took for the car to stop. Instead, we are given the initial speed (50.0 km/h = 13.9 m/s) and the distance over which the car stops (35 m).

To find the time it took for the car to stop, we can use another formula:

distance = initial velocity * time + (1/2) * acceleration * time^2

Since the car starts from rest (initial velocity = 0), the equation becomes:

distance = (1/2) * acceleration * time^2

Rearranging the equation, we get:

time = sqrt(2 * distance / acceleration)

Now let's substitute the given values into the equation. The distance is 35 m. Initially, the car was traveling at 13.9 m/s, which is equivalent to 0 m/s (since the car came to a stop).

Using the above equation, we can solve for time:

time = sqrt(2 * 35 / acceleration)

Next, let's calculate the time it took for the car to stop.