Question

Steve races to the nearest taco stand at lunchtime and sees that his pedometer recorded his peak speed at 70.9 70.9 cm/s. What was Steve's peak speed in kilometers per hour?

Answer 1

Answer:

70.9 cm/s = 2.55 km/h

Explanation:

Hi there!

We have the following equivalencies:

1 cm = 0.01 m.

If 1000 m ⇒ 1km

Then  0.01 m ⇒ (0.01 m · 1 km / 1000 m) = 1 × 10⁻⁵ km

Then: 1 cm = 1 × 10⁻⁵ km

1 h = 3600 s

Then, to convert cm into km we can multiply the given quantity in cm by

(1 × 10⁻⁵ km / 1 cm) and we will obtain kilometers.

Similarly, to convert seconds into hours, we can multiply the given quantity in seconds by ( 1 h / 3600 s) and we will obtain hours.

In this case:

$70.9 \frac{cm}{s}(\frac{1*10^{-5}km}{1cm})(\frac{3600 s}{1 h}) = 2.55 \frac{km}{h}$  (notice how the units cm and s cancel)