A car is traveling with a constant speed when the driver suddenly applies the brakes,causing the car to slow down with a constant acceleration of magnitude 3.50 m/s².If the car comes to a stop in a distance of 30.0 m,what was the car's original speed? A)10.2 m/s B)14.5 m/s C)105 m/s D)210 m/s E)315 m/s

Question

Quizplus · Accepted Answer

We can use the formula:

v^2 = u^2 + 2as

Where v is the final velocity (0 m/s), u is the initial velocity (unknown), a is the acceleration (-3.50 m/s^2), and s is the distance traveled (30.0 m).

Rearranging the equation, we get:

u = √(v^2 - 2as)
u = √(0^2 - 2(-3.50 m/s^2)(30.0 m))
u = √(210 m^2/s^2)
u = 14.5 m/s

Therefore, the car's original speed was 14.5 m/s. Choice B is the correct answer.

A Car Is Traveling with a Constant Speed When the Driver