A water-skier is pulled behind a boat by a rope that is at an angle of 13° and has a tension of 490 N. The water-skier has a mass of 49 kg. a. Draw a free-body diagram showing the forces acting on the skier. (She is being pulled to the right.) b. What are the magnitudes of the x- and y-components of the tension? c. What is the normal force acting on the skier?
try to draw an fbd with the water skier as a dot being pulled by a force at a 13 degree angle
|dw:1517250402253:dw|
the force is being applied at an angle
there are only two forces, the tension + gravity so there should only be two arrows
|dw:1517250459439:dw|
|dw:1517250475227:dw|
actually there's a normal force nvm 3 arrows
|dw:1517250513724:dw|
|dw:1517250504544:dw| you don't have to draw the box every time, most fbs just have a dot
anyway, for b) to resolve the tension into its x/y components it's just Fcos(theta) and Fsin(theta) as usual
f would be 490 right?
yes
490sin(13)=110.23 490cos(13)=477.44
good, units are N as usual
to calculate the normal for c) we need to consider the y-direction of the tension force as well as gravity|dw:1517251109800:dw|
net force = 0 = Fsin(theta) - mg + N solve for N
110.23-49(9.8)+n
= 0 then solve for N
369.97
good so 369.97 N = your ans
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