a-50-mathrmkg-man-stands-on-a-scale-that-measures-force-in-an-elevator-traveling-up-with-an-accelera

Question

A 50 $\mathrm{kg}$ man stands on a scale that measures force in an elevator traveling up with an acceleration of $g / 4 .$ What will the scale read?
(A) 375 $\mathrm{N}$
(B) 500 $\mathrm{N}$
(C) 575 $\mathrm{N}$
(D) 625 $\mathrm{N}$

Sachin Rao · Accepted Answer

in this problem, we have given a 50 KT. Man stands on a scale that measures force in an elevator, traveling up with an acceleration of G by four. So this is elevator. It is moving with acceleration in a forward direction. It is a cold G four. So we know that. I suppose this is men and we know that normal force, the skill will read the normal force. And we know that M G force will be in the downward direction. So when a lot. But it is moving in the right direction. We can write and yeah, minus mg should be cool too. I am into a so the normal force will be called, um G plus A. Or we can write. It is equal to mass, which is 50 kg into G plan Z by four, which is five g by four. So normal force will be equal to 5. 15 to 5. I don&#x27;t if we take G is equal to 10. So this is 10 by four. This is equal to 25 five. This is 6 25 new can. So the scale will read a force equal to 6 25 Newton Now we will check the oceans. So Option B is correct. Yeah. Yeah. And it is Answer for this question. Thank you.

Keshav Singh · Answer

in this problem. On the topic of Newton&#x27;s laws of motion, a man is standing on his scale in elevator. As the elevator rises, the man is has a mass of 75 kg and he notes the reading on the scale to be 825 Newtons. He wants to find the acceleration of the elevator. So if the force is 825 Newtons, this is the upward force exerted on the man by the scales. Then the upward acceleration of the men and hence the upward acceleration of the elevator is a Y and a y by Newton&#x27;s second law is the resultant force, acting in the vertical direction, divided by the mess of the men and the resultant force in the vertical direction is the force exerted on the scale 825 mutants minus the weight of the man which is gives mass times acceleration due to gravity. And all of this divided by the man&#x27;s mess. So we can simplify this and write this as 825 Newtons over the mess of the men minus G. So this is 825 Newtons divided by 75 kg, minus the acceleration due to gravity 9.8 m per square second, so calculating with the acceleration of the elevator and the man to be 1.2 m per square second.

Ze-Han Lee · Answer

All right. So in this problem was way, we know that Ah, person who weighs 100 new tis ah, step on the scale is actually Ah, you can see that f equal 800 new tests because initially it is This person is that rest. So this simple equal to m times cheat right on g here. We just used the 10 meters per second squared. So we say that the mass of the of this person equal eight able 80 kilograms. And if ah, if the person is except his accident except accelerating up weaves exaggeration a equal five meters second swift. And we can see that the fools on this person ah, delivered by the elevator equal f equal mess times G plus eight. Right, So this gives you 1200 Newton. So this is also the reading on the scale. All right?

Kian Maleki · Answer

we are talking about an elevator. So whenever you have a problem at elevator it&#x27;s very very useful. Two through the free body diagram that is the first said, we always want you to. So in the problem that we have an object sitting at the bottom of a Liberator. Well it obviously has some mess which gives us M. G. D. C. Is the weight downward. It also has some normal force which is the force that the surface puts on the object. The question said is interested to knowing um what is the reading of the scale. If you put a scale right underneath this object, the number that they scale reads is this value. And so what we call the normal force is the value that the scale reads if you put it under the object. So part A. It says the elevator is at rest. What we start from, we always start from the situation in problems like this, F is equal to a because the object is at rest. That means this acceleration is zero. So you get em time zero which is equal to zero. Now we have to write some of the forces. So um this force note that it&#x27;s a victor, it has a victor on top, what does that mean? That means you have to always break it down into the motion in the extraction and motion in the y direction. Motion in the X direction is just zeros. Everything next direction is zero. So we are not interested in the X direction, we are interested in the y direction. What are the forces in the Y direction? We have the normal force which has as a positive sign because it&#x27;s upward minus MG. Which is downward and that is equal to zero. So we end up with N. Is equal to MG. And we are interested in the value of and We write our mess which is 75 R. G. Which is gravity is 9.8. So we write 9.8 here and we end up that new tune. That normal force is seven 135 net. The question is asking what would their scale read in newton as well as in kilogram? So we know that this is what they scale reads as a newton, but what would you treat as kilograms? So what usually scale do they automatically divide this number By 9.8. And they showed that as a kilogram and if you divide this one, you get 75 kilograms, which is what this kid would read if it is saturating kilogram. Now, for part B, we&#x27;re going to start from exactly the same equation M. A. And now it&#x27;s saying that the elevator is moving good, but it&#x27;s moving at a constant velocity whenever it&#x27;s something is moving at constant velocity, it means E It means acceleration is equal to zero. That means I have exactly the same question. I want you compare this equation with this equation that we had up here, you can see it&#x27;s exactly the same. So I have to follow the exact same steps and I will end up with exactly the same answer which is The normal force is 735 Newton. And if I converted into clear Graham, I find that this Hillary 75 kilograms. Now, what was the answer to park? Si? Again, I start with the same equation if is the call to M. A. This equation is very important this time it&#x27;s a game moving at a constant velocity but it is moving downward. So again, because I have constant velocity, constant. We That means my acceleration is equal to zero and I followed the exact same step. A physical to zero. Notes that this equation. This is a question is exactly the same as what we had here. And I again end up with new With the normal force to be 735 Newtown And in kg will have 75 kilogram that would be what the scale would read. Now, part D is where things get slightly interesting. So again, I start with my diagram here because it came down here and it never hurts to through the free body diagram many times. We have MG here and we have in here this time again, I start with the same equation, it says that there is an acceleration and up the elevator is moving upward with the acceleration of three m per second square, that means this a is not zero anymore. So what we do again, we write the X direction and the wind direction in X direction. Everything is zero. So ffx zero in what direction we have, F F Y. I mean all the forces in what direction? Or the networks is in Y direction as you call to mass times, acceleration in the Y direction. So what were the forces we had in the Y direction? The forces we had in the wire direction are newton Are the normal force. You can see this one minus MG which is dis forced Is equal to this time is not equal to zero. Is he called aim? And are y acceleration is three. Now, I know what the mass is, I know what G is. I know this three. The only unknown in this problem is this end. So I have one equation with one unknown and I can sold this how I solved this one and is equal to three M. This one goes to the other side of the question plus 9.8. for GMM I can factor out the M that gives me 12.8. That is that some? I&#x27;m sorry, I just had an extra call sign over there which is MM is 75 And we end up with 960. No chance again. We want to convert this one into kilograms. So this is our final answer but we want to convert it into kilogram. If you want to convert it into kilogram, What s scales usually do internally is that we divide 960 By 9.8. That would give us 97.56 kg. And a sale would read this number and you can see it is higher than the actual mass of the object because the mass is 75. But what the scale reads is 97 0.56. Now for the last part part E we have the same situation except our acceleration this time is down work and We can write it as because it&#x27;s doesn&#x27;t work -3 media persic and the schools. So the direction of the acceleration is very important. Again, I start with the same equation. F is he called to M. A. We are only interested in the Y direction, in the Y direction I have normal force minus MG Is equal to mass times acceleration which is -3. This negative place a very, very important role in our calculations. So be very careful about that negative sign now again, a right. And is it called to negative through M plus M 9.8 which gives me negative three plus 9.8 times are masked and I want to compare this equation here with the one up here you see they are very similar. The only difference is one negative sign and that negative sign plays an important role here because I end up with Newton is equal to 6.8 Times are mass which was 75 and this gives us 510 Newton converted into kg 510, divided by 9.8. That gives us 52 kg, so these are the final answers.

Averell Hause · Answer

free body diagram for the elevator and inside the elevator there&#x27;s a scale. So we can say that if this is the free body diagram for the elevator, we can apply the sum of forces in the right direction. This week will m a y on this one equal force normal minus mg. Now, the question is asking us to not only find, um, the apparent, um mass, but also forced normal calculated. So here we can create You can find a relationship rather for force normal and say force normal is equal to the mass times acceleration in the right direction plus the acceleration to gravity. Now they&#x27;re reading on this scale In in kilograms will be the apparent weight off will be of the apparent wait the fourth normal divided by G the acceleration due to gravity so we can say forced normal kilograms. This, uh, subscript will denote the apparent weight in kilograms. This will equal m a wide plus g and then this will simply be divided by the acceleration due to gravity g. So, uh and then at this point, we can evaluate each case. So for the case, a, uh, the acceleration is zero so essentially the force normal rather the apparent weight forced normal kilograms and kilograms would be equal to the mass. And then the acceleration zero settle BMG divided by G, that cancels out. So this will equal Mm. And this is equaling 75 0.0 kilograms the weight of the person inside the elevator to find force normal itself. This would simply be equal to M G. And this is equaling 75 kilograms multiplied by 9.8 meters per second squared and this is equaling 735 new knees. Now for part B, however, a is equaling again zero and so the apparent weight is going to be the exact same force normal, of course, be the exact same as well. And this also applies for part C. So the first case where this changes is case deep where for case deep, we have an acceleration equal to 3.0 meters per second squared. And so at this point, we can solve for F they apparently and so this will be 75 kilograms multiplied by 9.8 plus three, divided by 9.8. And so this is giving us 98.0 kilograms For the force normal, this will be equal to 75 kilograms multiplied by three plus 9.8 meters per second squared. So the forced normal is going to equal 960 Newton&#x27;s and then finally for party we have a equaling negative 3.0 meters per second squared. So here the elevator&#x27;s actually going down. So forcing the apparent weight rather would be equal to 75 kilograms times 9.8 minus three all divided by 9.8. Once again, this is giving us 52 kilograms. Fourth normal would be equal to um, times a y plus G. Once again, this is equaling 75.0 kilograms times 9.8 months, six minus 336.8 meters per second squared and we find that this equals 510 millions. So that&#x27;s our final answer. That is the end of the solution. Thank you for watching

Eric Mockensturm · Answer

We&#x27;re told that we have a 70 kg person standing on a scale on an elevator. Uh it&#x27;s kind of a standard problem. And so the elevator is is moving and it may or may not have an acceleration. I&#x27;m gonna say a is positive upwards. So we have the normal forest, which would be the forest that the scale would read equals the weight, oh minus the weight equals mass times acceleration. Now if A is zero Then the normal forces the weight which is MG which is 736 newtons. And if the scale was using um G to convert that back into kg to mass, you get 75 kg. Because again, the scale is gonna measure force, it&#x27;s not gonna measure mass. But if it has a if it has a scale on their indicating mass, they&#x27;re basically just dividing through the forest by G. Now if it&#x27;s moving up At a constant speed, that means also that acceleration is again zero. So in that case we&#x27;ll n is generally B. M times G plus A. But A is zero. So again we get the same, it should measure the same weight and same mess If it&#x27;s going down at 3m/s. So that doesn&#x27;t matter because the acceleration is still zero if this is a steady speed. So we get the same measurements. Now we get different measurements when there&#x27;s an acceleration and when accelerating upwards at three m per second squared, we get an equals M times G plus A. Doing that out, we get that is 961 Newton. So the the scale will measure this. And if it&#x27;s using if it&#x27;s dividing through by G to measure kind of an effective weight Or an effective mass, you&#x27;ll get an effective mass of 97 9 kg. And now, if it&#x27;s decelerating at three m per second squared, that means that A. Is negative here, and so we get something less than this, And turns out to be the scale is weighing is measuring 511 Newton&#x27;s. And again, if there&#x27;s if we&#x27;re just dividing to get a massive, we&#x27;re just dividing by G. We&#x27;ll get this effective mass 52.1 kg.

Problem

A mechanical wheel initially at rest on the floor…

Problem 29 Easy Difficulty

A 50 $\mathrm{kg}$ man stands on a scale that measures force in an elevator traveling up with an acceleration of $g / 4 .$ What will the scale read?
(A) 375 $\mathrm{N}$
(B) 500 $\mathrm{N}$
(C) 575 $\mathrm{N}$
(D) 625 $\mathrm{N}$

Answer

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