You can do #18 in one of two ways. either you can use kinematics or you can use conservation of energy.
If you use kinematics then you need the speed that you found in #17. That's vo, but you need the angle from the horizontal to find the x- and y- components of the initial velocity. Notice that the skier starts from the end of the ski jump which is at a height above ground.
If you use conservation of energy then you can say that the total energy at the beginning of the ski jump (at the top) is equal to the total energy at the skier's maximum altitude. Notice that he started from rest at the top of the ski jump. Also notice that since he is moving in a parabola (not straight up and down), his kinetic energy at his maximum altitude will be K=(1/2)mv^2, and the v will be his horizontal velocity since his vertical velocity is zero at the top. Maybe somebody else can explain it better?
2 comments:
You can do #18 in one of two ways. either you can use kinematics or you can use conservation of energy.
If you use kinematics then you need the speed that you found in #17. That's vo, but you need the angle from the horizontal to find the x- and y- components of the initial velocity. Notice that the skier starts from the end of the ski jump which is at a height above ground.
If you use conservation of energy then you can say that the total energy at the beginning of the ski jump (at the top) is equal to the total energy at the skier's maximum altitude. Notice that he started from rest at the top of the ski jump. Also notice that since he is moving in a parabola (not straight up and down), his kinetic energy at his maximum altitude will be K=(1/2)mv^2, and the v will be his horizontal velocity since his vertical velocity is zero at the top. Maybe somebody else can explain it better?
Good luck.
Thank you doctor....again.
Post a Comment