Question

First question I'm having trouble with:

-An arrow is shot at a target 60m away (horiz), and 24m high (vert) - [picture of uneven trojectary is given]
Find the arrow's initial speed.

Second one goes something like this:
- Car is traveling 170km/h down a road, and a radar gun on a 28 degree angle spots the car. What is the car's speed relative to the radar gun? (I get 150Km/h as my answer, correct?)

Thanks!

Answer 1

Yes, on the second.

First: Solve it in the vertical, and horizontal.

Vertical
24=vi*sinTheta*time -1/2 g t^2
Horizontal
60=vi*cosTheta*time

From this, three unknowns, two equations, there are an infinite number of solutions. You have to know more.