Answer:
- <u>4s</u>
- <u>50m/s (straight)</u>
Explanation:
I will answer in English.
The translated question is:
- <em>3. In a race whose route is straight, a motorcycle circulates for 30 seconds until it reaches a speed of 162.00km / h. If the acceleration remains the same, how long will it take to travel the remaining 200 meters to pass the finish line and at what speed will it do so?</em>
<h2>Solution</h2>
<u>1. Time</u>
First, you must calculate the acceleration, a, starting from rest (V₀ = 0), with a time fo 30 seconds, and final veloficty, V₁, of 162.00km/h.
Convert 162.00km/h to m/s:
- 162.00km/h × 1,000m/km × 3600s/h = 45m/s
- a = (V₁ - V₀)/t = (45m/s - 0) / (30s) = 1.5m/s²
Now, you can calculate the time to travel 200 meters
The most direct equation is;
Where you know:
Use the quadratic formula with a = 0.75, b = 45, and c = -200
![t=\dfrac{-45\pm\sqrt{45^2-4(0.75)(-200)}}{2(0.75)}](https://tex.z-dn.net/?f=t%3D%5Cdfrac%7B-45%5Cpm%5Csqrt%7B45%5E2-4%280.75%29%28-200%29%7D%7D%7B2%280.75%29%7D)
Discard the negative value. The positive value is t = 4.1565s
Round to one significant figure: 4s ← answer
<u>2. Velocity</u>
The speed or magnitude of velocity may be calculated using the equation:
With:
- V₂ = 45m/s + 1.5m/s² × 4.1565s = 51m/s ≈ 50m/s, along the same straight line ← answer