question_answer

A crow is sitting on the top of a house. The house is 40 m high. The angle of elevation of the crow as seen from a point on the ground is \[45{}^\circ \]. The crow flies away horizontally and remains at a constant height. After 3 seconds the angle of elevation of the crow from the point of observation becomes\[30{}^\circ \]. Find the speed of the crow.

A)  9.76 km /hr                  

B)  29. 28 m/s

C)  9.76 m/s

D)  29.28 km/hr

E)  None of these