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roam
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Homework Statement
[PLAIN]http://img237.imageshack.us/img237/6677/incline.gif
A snow sled with a child secured safely to it has a total mass of 83.0 kg. It is lowered at a constant speed of 1.9 ms−1 down a slope of angle 41.0° with respect to the horizontal (as shown above) for a distance d = 14.0 m. The coefficient of kinetic friction between the sled and the snow is 0.09.
g = 9.8 ms–2. Air resistance is negligible at these speeds.
I have calculated the friction force to be 55.3, and the magnitude of the reactive force, N, on the sled to be 614.49 Newtons.
Then the question asks:
Suppose the rope suddenly snaps at its point of connection with the sled after traveling the distance d. Determine the drag force acting on the sled when it reaches a terminal speed of 8.4 ms−1.
The Attempt at a Solution
What does the question mean by the "drag force acting on the sled "? Is it reffering to the force that pulls the sled down the incline? I know that force is equal to
[tex]mg sin \theta = (83 \times 9.81) sin(41)= 534.18[/tex]
But this is wrong because the correct answer has to be 478 N.
Another approach I can think of is to find the time using dv=t= 117.6 and acceleration by [tex]a=v/t \Rightarrow a =\frac{8.4}{117.6}=0.07[/tex] then plug this into [tex]\sum F_x=ma_x=83 \times 0.07=5.9[/tex]. Which is again wrong...
Can anyone help?
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