Acceleration on an Incline: Calculating Net Acceleration and Final Speed

AI Thread Summary
To calculate Spinka's net acceleration on a 34-degree incline with a coefficient of friction of 0.198, the net force equation must include both gravitational and frictional forces. The correct formula is F_net = mg(sinθ) - μmg(cosθ), leading to the acceleration a = g(sinθ - μcosθ). After substituting the values, the net acceleration can be determined. Kinematic equations can then be used to find Spinka's final speed after 6.60 seconds. Understanding these calculations is crucial for solving similar physics problems effectively.
RingWraith2086
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Question: The record for grass skiing was set blah blah blah. Suppose it took Spinka 6.60 s to reach his top speed after he started from rest down a slope with a 34 degree incline. If the coefficient of friction between the skis and the grass was 0.198, what was the magnitude of Spinka's net acceleration? What was his speed after 6.60 s?

Here's what I've done:
I thought a=g(sinTheta)
Which gives me
a = 9.81(sin34)
a = 5.486 m/s2,
which isn't right. What am I doing wrong?
 
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Don't forget the friction:

F_{\rm net} = ma = mg\sin\theta - \mu mg\cos\theta

Solve for a (you'll see that m cancels out) and then use kinematics to get the speed part.
 
Well you just seem to know everything don't you? Maybe once I get through a quarter of physics I'll be able to help people too. Thanks once again.
 
Originally posted by RingWraith2086
Well you just seem to know everything don't you? Maybe once I get through a quarter of physics I'll be able to help people too. Thanks once again.

If only I did... Well, I'm glad I knew enough to help you here. It's also good to hear your willing to help when you can too. Keep up the good work.
 
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