Answer to Question #691 in Mechanics | Relativity for bobby

Question

A stone is projected from ground level at 86 m/s. Its speed when it reaches its highest
point is 46 m/s. Find the angle of its projection.

Answer 1

Let V0x, V0y be projections. At the highest point V0y=0, V0x=46 m/s - is constant.
V0x=V0*cos(a).
46=86*cos(a);
cos(a)=0.53;
a=arcos(0.53)=57.67
Answer: the angle is 57.67