A driver notices an upcoming speed limit change from 45 mi/h (20 m/s) to 25 mi/h (11 m/s). If she estimates
the speed limit will change in 50 m, what acceleration is needed to reach the new speed limit before it begins?

Respuesta :

Answer:

-2.79 m/s²

Explanation:

Given:

v₀ = 20 m/s

v = 11 m/s

Δx = 50 m

Find: a

v² = v₀² + 2aΔx

(11 m/s)² = (20 m/s)² + 2a (50 m)

a = -2.79 m/s²

Round as needed.

Explanation:

Given that,

Initial speed of the vehicle, u = 45 mi/h = 20 m/s

The final speed of the vehicle, v = 25 mi/h = 11 m/s

The speed limit will change in 50 m i.e. the distance is, d = 50 m

To find,

The acceleration of the vehicle that is needed to reach the new speed limit before it begins.

Solution,

Let a is the acceleration of the vehicle. It can be calculated using third equation of motion i.e.

[tex]v^2-u^2=2ad[/tex]

Solving for a.

[tex]a=\dfrac{v^2-u^2}{2d}[/tex]

Put all the values,

[tex]a=\dfrac{11^2-20^2}{2(50)}\\\\a=-2.79\ m/s^2[/tex]

Answer:

The acceleration of the vehicle is [tex]2.79\ m/s^2[/tex] and it is deaccelerating.

Reference:

https://brainly.com/question/12550364

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