A blink of the eye lasts about 500 ms. If a pilot is flying an Airbus A320 at 1040 km/h, roughly how far does the aircraft travel during that time?

Step-by-step solution

1. 1

   Convert the blink to seconds. $500\text{ ms}=0.5\text{ s}$ Mixing milliseconds with $\text{km/h}$ is what makes this question error-prone, so fix the units first.

2. 2

   Convert the speed to metres per second. Multiply by $1000$ and divide by $3600$: $v=\frac{1040\times 1000}{3600}=\frac{1040}{3.6}\approx 288.89\text{ m/s}$

3. 3

   Apply the uniform-motion formula. $s=vt=288.89\times 0.5\approx 144.4\text{ m}$

4. 4

   Round to the listed choice. $144.4\text{ m}$ is closest to $144\text{ m}$, so the answer is A.

5. 5

   Sanity-check the size. In one full second the plane covers about $289\text{ m}$, roughly three football pitches; half of that is about $144\text{ m}$, which confirms the order of magnitude.