- #1
dnt
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Homework Statement
Find the readings on each of the balances in these 4 situations (strings are massless and incline is frictionless):
(sorry about the photo - don't know how to fix it)
Homework Equations
F=ma, W=mg
The Attempt at a Solution
1) Seems easy enough. I am pretty sure the balance would just read 98 N since the tension above equals the weight of the mass below.
2) I am having a little trouble with this one. I cannot tell if its going to be 196 N (98 N from each of the weight pulling down on each end) or just 98 N. Each of the blocks has a net force equation of:
F = W - T = ma
98 - T = 0
T = 98 N (T, the tension, is what the scale will read, correct? Thats where the answer comes from?)
so I get the tention in the string is 98 for both but I don't know how to combine the two net force equations into a single answer for the balance reading.
3) the block has a net force equation of:
F = W - T - T = ma
W - 2T = 0
W = 2T
so the tension in the string/balance reading would be half of the blocks weight = 49 N.
4) I know I need the component of the blocks weight on this one due to the incline. And that should be Wsin30 = 49.
so the net force equation here is:
F = Wsin30 - T = ma
T = Wsin30 = 49 N
is that the correct answer? What about that other 10 kg block above? How does it get included into the problem (if at all?)
thanks.