Question
Physics Question on Motion in a plane
An arrow is shot into air. Its range is 200 m and its time of flight is 5 s. If g = 10 ms−2, then the horizontal component of velocity of the arrow is
A
12.5ms−1
B
25ms−1
C
31.25ms−1
D
40ms−1
Answer
40ms−1
Explanation
Solution
T = g2usinθ \hspace20mm ..(i) Also horizontal range R = ucosθ×t R = gucosθ×2usinθ \hspace20mm ..(ii) Given T = S and R = 200 ∴ From Eqs. (i) and (ii), we get 5 = g2usinθ \hspace20mm ..(iii) 200 = g2u2sinθcosθ \hspace20mm ..(iv) Dividing E (iv) by E (iii), we get 5200=ucosθ=40ms−1