Question

A racing car traveling with constant acceleration increases its speed from 10 m/s to 30 m/s over a distance of 60 m? How long does this take?

Answer 1

Answer:

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Explanation:

Answer 2

Answer:

The time taken by the car to travel the distance of 60 m is 3 seconds.

Explanation:

The racing car is moving with a constant acceleration. The initial velocity (u) of the car is 10 m/s and the final velocity (v) is 30 m/s. The distance (S) covered by the car is 60 m. Then the acceleration (a) can be found using the 3rd equation of motion as:

  v² = u² + 2aS

⇒ a = (v² - u²) ÷ 2S

      = (30² - 10²) ÷ (2 × 60)

      = (900 - 100) ÷ (120)

      = 800 ÷ 120

∴ a = 6.67 m/s²

Now we can calculate the time taken using the 1st equation of motion.

   v = u + at

⇒ t = (v - u) ÷ a

     = (30 - 10) ÷ 6.67

∴ t = 2.99 ≈ 3 sec