physics
posted by teamjakeward .
please show me how to do this in steps.
A track star in the long jump goes into the jump at 12 m/s and launches herself at 20.0degrees above the horizontal. What is the magnitude of her horizontal displacement?
(assume no air resistance and that
Ay= g = 9.81 m/s^2)
thanks :)

Her vertical component of velocity at takeoff is
Vyo = 12 sin 20 = 4.10 m/s
and her horizontal component is
Vx = 12 cos 20 = 11.28 m/s.
The horizontal component remains constant during the jump.
Use the vertical velocity component to determine how long she is in the air before hitting the ground. Call that time T
Vo = g T/2
T = 2 Vo^2/g
The length of the jump is Vx*T
= 2 (Vo^2/g) sin 20 cos 20
= (Vo^2/g) sin 40