Rain falls vertically downward at 20 m/s. A car moves horizontally at 20√3 m/s. The car has a vertical windshield. The rain strikes the windshield at an angle θ with the horizontal normal to the windshield. Then θ equals:
Options

Question

Rain falls vertically downward at 20 m/s. A car moves horizontally at 20√3 m/s. The car has a vertical windshield. The rain strikes the windshield at an angle θ with the horizontal normal to the windshield. Then θ equals:

Options

G1 Physics · Accepted Answer

In the car frame, the relative rain velocity has horizontal component 20√3 m/s opposite the car and vertical component 20 m/s downward. The normal to a vertical windshield is horizontal, so tanθ = 20/(20√3) = 1/√3. Therefore θ = 30°. Hence option A is correct.