# Answer to Question #691 in Mechanics | Relativity for bobby

Question #691

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.

point is 46 m/s. Find the angle of its projection.

Expert's answer

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

V0x=V0*cos(a).

46=86*cos(a);

cos(a)=0.53;

a=arcos(0.53)=57.67

Answer: the angle is 57.67

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