Acceleration is change in velocity over change in time. Your Δv is +13.9, since you increased speed by 50 km/h which is 13.9 m/s, and your Δt is 10s. 13.9/10 = 1.39 m/s^2, the standard units for acceleration. Make sense?
If you look on the periodic table you will see the top group elements depending on how the elements relate to each in the column. All of the elements in that column show they all have 1 electron in their valence shell. Some of the chemicals in that family or group are Sodium, Lithium, Potassium. The are very reactive because they only have one electron and what 7 more to become stable.
<h3><u>Answer</u>;</h3>
= 0.6
<h3><u>Explanation</u>;</h3>
Using Pythagoras theorrem
Base² + height ² = Hypotenuse²
Thus;
Base² = 15² - 12²
= 81
Base = √81 = 9
But; cosine = adjacent/hypotenuse
Hence; cos θ = 9/15
<u>= 0.6 </u>
I'm not from that school but I can help you.
Maybe the word could be converted?