Physics work problem - mastering physics

AI Thread Summary
The discussion revolves around calculating the work done by a 15-Newton force using the equation W = F·s·cos(θ). The initial calculation yielded W = 15*cos(140°)*160 = -1838.506, but the user received feedback from Mastering Physics indicating potential errors in rounding or significant figures. A key point raised is the requirement for angle measures to be in radians, which may impact the calculation. Despite this, the user argues that the cosine value should not affect the overall answer. The conversation highlights the importance of precision in calculations and the nuances of using different angle measurement systems in physics problems.
Shayna
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Physics work problem -- mastering physics

Homework Statement


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Find the work W done by the 15-Newton force.

Homework Equations


W=\vec F\cdot\vec s=\left|\vec F\right|\left|\vec s\right|\cos \theta

The Attempt at a Solution


W= 15*cos140*160 = -1838.506
I don't know why mastering physics was telling me "Not quite. Check through your calculations; you may have made a rounding error or used the wrong number of significant figures."
 
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I don't know if you already figured this out, but the only thing I can think of (and it's not really even related to the error you were getting) is that Mastering Physics requires angle measures to be in radians.
 


yes but that shouldn't be affecting the answer though, cos140degree = cos(14/9)pai
Thanks though
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
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Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
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