Question

A drone is flying with a speed of 120 ft/h at an angle of 40 degrees from the ground , and a 25 ft/h blowing east. What is the resultant speed of the drone ?

Answer 1

As per given by the question,

There are given that the angle is 40 degrees and speed of 120 ft/h.

Now,

From the question,

here use the cosine rule,

Then,

cosine rule is,

`s=\sqrt{(25)^2+(120)^2+2*25*120\cos(40)^{}}`

Now,

`\begin{gathered} s=\sqrt[]{625+14400+50*120*0.76_{}} \\ =\sqrt[]{15025+4560} \\ =\sqrt[]{19585} \\ =139.9 \\ =140 \end{gathered}`

The resultant speed is 140 ft/h.

Hence, the option second is correct.