Question

A skateboarder starts from rest and accelerates a distance of 485 m reaching a final velocity of 20.0 m/s. How long does it take?

Answer 1

Hello, first we have to look at this part; "The skater starts from rest", which means that the initial speed is zero meters per second.

Once we know that the initial velocity is zero, to calculate the time, we apply the following equation:

s = [(Vo + V) / 2] × t

Like Vi value, is zero meters per second, let's do a simplification in the equation:

s = (V / 2) × t

Data:

s = Distance = 485 m

V = Final velocity = 20 m/s

t = Time = ?

Let's replace the equation according our data:

485 m = (20 m/s / 2) × t

• Divide the velocity:

485 m = 10 m/s × t

• Product's divided:

485 m / 10 m/s = t

• Resolve last operation:

t = 48.5 s

Result:

Takes 48.5 seconds to reach that speed.