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MissTica
3 years ago
12

The safe load, L, of a wooden beam supported at both ends varies jointly as the width, w, the square of the depth, d, and invers

ely as the length, l. A wooden beam 3in. wide, 6in. deep, and 11ft long holds up 1213lb. What load would a beam 6in. wide, 3in. deep and 12ft long of the same material support? (Round off your answer to the nearest pound.)
Physics
1 answer:
soldier1979 [14.2K]3 years ago
6 0

Answer:

L' = 555.95 lb

Explanation:

Analyzing the given conditions in the question, we get

The safe load, L is directly proportional to width (w) and square of depth (d²)

 also,

L is inversely proportional length (l) i.e L = k/l

combining the above conditions, we get an equation as:

 L = k(wd²/l)

 now, for the first case we have been given

w = 3 in

d = 6 in

l = 11 ft

L = 1213 lbs

 thus,

1213 lb = k ((3 × 6²)/11)

or

k = 123.54 lbs/(ft.in³)  

Now,

Using the calculated value of k to calculate the value of L in the second case  

in the second case, we have

w = 6 in

d =3 in

l = 12 ft

Final Safe load L' =  123.54 × (6 × 3²/12)

or

L' = 555.95 lb

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3 years ago
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egoroff_w [7]

Answer:

The resultant force would (still) be zero.

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Before the 600-N force is removed, the crate is not moving (relative to the surface.) Its velocity would be zero. Since its velocity isn't changing, its acceleration would also be zero.

In effect, the 600-N force to the left and 200-N force to the right combines and acts like a 400-N force to the left.

By Newton's Second Law, the resultant force on the crate would be zero. As a result, friction (the only other horizontal force on the crate) should balance that 400-N force. In this case, the friction should act in the opposite direction with a size of 400 N.

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