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A lift is moving up with acceleration of 3.675m/s^2 the weight of man is increases by 37.5% decreases by 37.5% remains same I want answer with full solution.

A lift is moving up with acceleration of 3.675m/s^2 the weight of man is
  1. increases by 37.5% 
  2. decreases by 37.5%
  3. remains same
I want answer with full solution.

Grade:11

89 Answers

Neeti
571 Points
8 years ago
pseudo force acting on the body = mx 3.675. downwards, therefore net weight of man = mg + m x 3.675 and so weight increases by 37.5%
 
Please feel free to ask follow up doubts and approve the answer if you like it :)
Ananya Sharma
36 Points
8 years ago
Can i ask you any other question in this same comment box(neeti)
Neeti
571 Points
8 years ago
Yes absolutely :) You can also post your question separately . there is a column on the right side of the page. That will help you attach an image of your doubt if there is any :) 
Ananya Sharma
36 Points
8 years ago
But on the askiitians i only found you answering the questions this much quicker so i only need response from your end so will u give me reply ASAP(As soon as possible) as i tomorrow have to sumbit by HW
Neeti
571 Points
8 years ago
yes yes absolutely :) I’m online right now post as many questions as you want and i will reply ASAP :) you can post them separately i’d be easier for me to answer, i might miss out a question in the comment box if you send too many at once. So post them separately and i’ll explain each one to you as quickly as i can :)
Ananya Sharma
36 Points
8 years ago
Thanks a lot
 
Neeti
571 Points
8 years ago
You are most welcome :) I’m here to solve doubt :D so keep them coming :)
Neeti
571 Points
8 years ago
In fact, whenever you want to get your doubts cleared you can post them. even in the middle of the night – i’d reply as soon as i see the question in the morning
and even if i dont’ reply instantly, you’d get a reply from me within 10-15mins if i’m not busy doing something else :) 
Ananya Sharma
36 Points
8 years ago
I have posted few of them 
Neeti
571 Points
8 years ago
it’s not coming in the forum list . when did you post them ? i can’t find the questions
Ananya Sharma
36 Points
8 years ago
Just now
Neeti
571 Points
8 years ago
I can’t find it. Copy and paste the links of the questions in the comment box.
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/i-want-answer-with-full-solution_129632.htm
Neeti
571 Points
8 years ago
Acha do one thing, post the questions here itself. I’m sorry this must’ve caused you inconvenience but i just can’t seem to find the questions i don’t know why they won’t show up in my forum questions.
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/i-want-answer-with-full-solution_129633.htm
Ananya Sharma
36 Points
8 years ago
Are links working
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/i-want-ans-with-full-soln_129634.htm
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/i-wnat-ans-with-full-soln_129635.htm
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/i-want-ans-with-full-soln_129636.htm
Ananya Sharma
36 Points
8 years ago
Are they working
Ananya Sharma
36 Points
8 years ago
I do have answers of it but i want solutions
If you need answers then tell me i’ll give you
Neeti
571 Points
8 years ago
Yes the links are working. I’ll answer them one by one. I’ve answered one already :) go check it out and try it. if you’re still unable to solve it let me know :)
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/ans-with-full-soln_129640.htm
Ananya Sharma
36 Points
8 years ago
The acceleration with which an object of mass 100kg be lowered from a roof using a cord with a breaking strength of 60kg weight without breaking the rope is
  1. 2m/s square    b. 4m/s square    
Ananya Sharma
36 Points
8 years ago
A man weighs 80kg He stands on a weigheing scale in a lift which is moving upwards with a uniform acceleration of 5m/s square what would be reading on scale take g=10m/s square
  1. 1200 N b. Zero
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/ans-with-full-soln_129641.htm
Ananya Sharma
36 Points
8 years ago
A girl of weight W is sitting on an electric swing rotating in a vertical plane She feels her weight to have increased by 25% as swing goes up What weight she should experience when swing come down
Neeti
571 Points
8 years ago
A man weighs 80kg He stands on a weigheing scale in a lift which is moving upwards with a uniform acceleration of 5m/s square what would be reading on scale take g=10m/s square
  1. 1200 N b. Zero
 
 
The answer for this question is :
Since the lift is moving upwards pseudo force acts downwards = 80 x 5 = 400N 
 
This adds to the weight of the man which is 80 x 10 = 800 N therefore the total weight shown on the weighing machine is 1200 N :)
 
Neeti
571 Points
8 years ago
Please approve the answers i’m actually working hard to give you quick and right solutions so i’d be really happy if you approve the answers :)
Neeti
571 Points
8 years ago
A girl of weight W is sitting on an electric swing rotating in a vertical plane She feels her weight to have increased by 25% as swing goes up What weight she should experience when swing come down
 
The solution for this question:
 
when going up, the final weight of the body increases due to pseudo force acting on the body.
W + 25/100 W is the total weight therefore 25/100 W is due to pseudo force. when coming down,  this force acts upwards so her weight decreases by 25/100 W 
Neeti
571 Points
8 years ago
The accelaration with which a body of 100kg should be lowered using a cord of breaking strength 60kg is :
 
breaking strength is the maximum tension the string can bear whihc is 60 kg means 600N assuming g = 10m/s2.
 
the equation will me 
mg – T = ma
 
100 x 10 – 600 = 100x a this gives us a= 4m/s2
Neeti
571 Points
8 years ago
There you go :) you have all the answers. Please approve the answeres you found useful. i’m sure you must’ve solved all of them by now. So please  approve the answers :)
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/ans-with-full-soln_129642.htm
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/ans-with-full-soln_129641.htm
Neeti
571 Points
8 years ago
Follow each link you sent me. I’ve answered them :) and i’m working on the ones you just sent me
Ananya Sharma
36 Points
8 years ago
Really Thanks a lot u helped me a lot
  1. A mass is suspended from roof of a car by a string While the car has constant accn a, The string makes an angle og 60 degree with vertical if g=10 m/s square value of a is:
  1. 10(3)1/2 m/s2      b. 5 m/s square
Neeti
571 Points
8 years ago
Done, solved them. :)
Neeti
571 Points
8 years ago
See the links, and the answers that i’ve posted there. I’ve solved all of them. :) If you like them approve them too :)
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/ans-with-full-soln_129646.htm
Neeti
571 Points
8 years ago
A mass is suspended from roof of a car  by string..... square of value of a is:
 
Here also pseudo force acts on the body. Since car is moving with accelaration, a pseudo force acts on the body backwards and the gravitational force acts on the body downwards.  so accelaration a backwards and accelaration g downwards. Draw the diagram carefully then use the data and equate and you’ll get the answer :)
Neeti
571 Points
8 years ago
and you are most welcome :) I’m here to help students like you :) 
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/ans-with-full-soln_129647.htm
Neeti
571 Points
8 years ago
Follow the link i’ve answered it too :)
Ananya Sharma
36 Points
8 years ago
A force of 6N acts on a body at rest of mass 1kg During this time the body attains a velocity of 30m/s. The time for which the force acts on the body is:-
  1. 10 seconds    b. 5 seconds
Ans. with full soln
Ananya Sharma
36 Points
8 years ago
A truck of mass 500kg moving with constant speed 10m/s If sand is dropped into the truck at constant rate 10kg/min, the force required to maintain the motion with constant velocity is:-
  1. 5/3N      b. 3/2N
Ans. with full soln.
Ananya Sharma
36 Points
8 years ago
A 1kg particle strikes a wall with velocity 1m/s at an angle 30 degree with the normal to the wall and reflects at the same angle If it remain in contact with wall for 0.1s then force is:-
  1. 0     b. 10(root3)N
Ans. with full soln.
Ananya Sharma
36 Points
8 years ago
A cricketer catches a ball of mass 150gm in 0.1sec moving with speed 20 m/s then he experiences force of:-
  1. 300 N     b. 30N
I want answer with full solution
Neeti
571 Points
8 years ago
A force of 6N acts on a body at rest of mass 1kg.... the time for which force acts on body:
 
We know that F x \Deltat = \Delta
here u= o and v = 30m/s therefore \Deltap = 1x 30 = 30.
 
and force F = 6N, putting the values of both, you get \Deltat :)
Ananya Sharma
36 Points
8 years ago
A body of mass 2kg moving on a horizontal surface with an initial velocity of 4m/s comes to rest after 2sec If one wants to keep this body moving on the same surface with velocity of 4m/s the required force is:-
  1. 4 newton      b. zero newton
Ans with full soln
Neeti
571 Points
8 years ago
“ a truck of mass 500kg...force required to maintain motion”
 
same concept, here F = dm/dt x v where v of sand is = v of truck and dm/dt is 10kg per minutes i.e. 10/60kg per second. 
so F = 10/60 x 10 = 100/ 60 :)
Ananya Sharma
36 Points
8 years ago
At a place where the accelaration due to gravity is 10 m/s2 a force of 5kg weight acts on a body of mass 10kg initially at rest The velocity of body after 4 second is:-
  1. 20m/s      b. 10m/s
Ans. with full soln
Ananya Sharma
36 Points
8 years ago
Gravels are dropped on a conveyor belt at rate of 0.5 kg/sec. The extra force required in newtons to keep the belt moving at 2m/s is:-
  1. 1N      b. 4N      c. 0.5 N
Ans, with full soln
Ananya Sharma
36 Points
8 years ago
A man is standing at a spring platform . Reading of spring balance is 60kg wt . If man jumps outside platform then reading of spring balance :
  1. Decreases     b. First increases then decreases to 0
Ans, with full soln
Neeti
571 Points
8 years ago
“ 1kg particle strikes wall with velocity 1m.s/... force is”
 
angle to the normal is 30 so p perpendicular to wall  is pcos 30. and during collision with wall only the perpendicular component changes. so \Delta p = pcos30 – ( – pcos 30) = 2pcos 30 
time also given,
We know that F x \Deltat = \Deltap, you have \Deltap and \Deltat so you get F :)
Ananya Sharma
36 Points
8 years ago
In a tug of war two teams apply 1000 Newton force at ends of rope which is found in equilibrium the tension at rope is
  1. 0     b. 1000 newton
Ans with full soln
Neeti
571 Points
8 years ago
“ a cricketer catches a ball.....he experiences a force of”
same concept. mass given, initial velocity given. since he catches the ball so final velocity is zero. so you find the change is momentum. time is also given and F x \Deltat = \Deltap so on applying the formula and using values you get F :)
Neeti
571 Points
8 years ago
Try a few questions yourself and let me know what your doubts are :)
Ananya Sharma
36 Points
8 years ago
If a 5kg mass is suspended by a spring balance in a lift which is accelaration downwards at 10m/s2 The reading of balance (g=10m/s square):-
a. less than 5kg weight
  1. 0
ans with full soln
Neeti
571 Points
8 years ago
A body of mass 2kg moving on a horizontal surface with an initial velocity of 4m/s comes to rest after 2sec If one wants to keep this body moving on the same surface with velocity of 4m/s the required force is:-
 
you have initial veloctiy, final velocity = 0 and time given so find accelaration. mass x this accelaration = retarding force acting on body possibly due to friction. Calculate that force and so an equal and opposite force should be applied to keep the body moving with velocity 4m/s
Ananya Sharma
36 Points
8 years ago
Now i do understant the things as of the questions to which i asked you
Doubt ratio was i did 150 questions successfully and around 35 to 37 are doubts now they are cleared thanks a lot now i can’t understand spring balance problems properly
and i solved each of yours they were all setted to my mind.
Neeti
571 Points
8 years ago
“ at a place where accelaration.....velocity after 4seconds”
 
i’m assuming that force is acting horizontally and body is moving horizontally.  you have force and mass so calculate accelaration and then apply v = u + at :)
Neeti
571 Points
8 years ago
“gravels are dropped....the extra force required in newtons” 
same as the question you sent about a truck moving and sand particle being thrown. So try this one yourself and let me know if you’re still unnable to and i’ll help you :)
Ananya Sharma
36 Points
8 years ago
I hope i’m not troubling you
As this do happen once in a week as i solve 1000’s of questions and i do clear all the doubts on one specific day so this is the part of that day.
Sorry if i’m troubling you.
Neeti
571 Points
8 years ago
Excellent :) Try solving as many questions as possible. And yes whenever you have a doubt you can post it here and i’ll help you :) for spring balance questions the concept is the same. you have to apply the concept of tension, and for measurting weight, you have to see if the frame of reference is under going accelaration or not, if yes, pseudo force will act on the body and then decide the direction of pseudo force and equate with weight due to gravity. :)
Ananya Sharma
36 Points
8 years ago
Yah that gravel one is being solved i got the ans
Neeti
571 Points
8 years ago
No No not at all. I’m actually very glad that i got to clear your doubts. You know i’m a student too but i love teaching so it’s actually great that i can finally get to teach. You can ask me anything, botany chemistry zoology. :) 
Ananya Sharma
36 Points
8 years ago
hmmm i taught you i’m hesitating you but no issue from my end to you that;s great
Neeti
571 Points
8 years ago
“ 5kg man suspended by a spring balance in a lift....” 
apply the concept of pseudo force because the frame of reference is accelarating. since accelaration is downwards the pseudo force is upwards so net weight of the man gets reduced. mg – ma. Try it and let me know if you need help :)
Neeti
571 Points
8 years ago
“ in a tug of war.....”
In this question since there is equilibirum , net force on both ends will be zero therefore force applied will be equal to the tension on that side of the rope so T= 1000N for each end.
Neeti
571 Points
8 years ago
and no problem. You can get all of your doubts cleared here :) I’ll help you out with biology too, i assume you’re preparing for medical. so don’t worry about it :)
Ananya Sharma
36 Points
8 years ago
 
I got the tug of war one 
Really how to thank to you
 
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/ans-with-soln_129656.htm
Neeti
571 Points
8 years ago
You are welcome :) i couldn’t solve the wedge one i’m not sure about it. wait till tomorrow morning and some other askiitian expert will hopefully solve it :)
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/ans-with-full-soln-if-possible-give-full-for-this_129657.htm
Ananya Sharma
36 Points
8 years ago
 
I think ur an iit jee adv passed with under 500 AIR
Neeti
571 Points
8 years ago
haha no unfortunately i’m not :P I just answered my AIPMT :) 
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/ans-with-soln_129659.htm
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/ans-with-full-soln_129660.htm
Ananya Sharma
36 Points
8 years ago
I’m also a paid member on meritnation.com
are u dere
Neeti
571 Points
8 years ago
And no i’m not on meritnation. I’ve only just finished my entrances so no one’s gonna keep me as a tutor :P 
Neeti
571 Points
8 years ago
You keep posting your doubts i’ll solve them tomorrow morning :) study hard. all the best :)
Neeti
571 Points
8 years ago
Did you check all the solutions i posted? Feel free to ask any other doubt.. I’d be more than happy to help =)
Ananya Sharma
36 Points
8 years ago
http://www.askiitians.com/forums/General-Physics/i-got-the-equations-but-can-t-get-the-answer-i-wa_129771.htm
Ananya Sharma
36 Points
8 years ago
Did u got my question link(neeti)?
Neeti
571 Points
8 years ago
Yes i did, give me 2 minutes :)
Forum Team
94 Points
8 years ago
Hi Neeti & Ananya,
 
Please discuss only 1 question in one thread. For every new question, post it separately otherwise answerer will not be able to get more than one approvals.
 
Forum Team
Ananya Sharma
36 Points
8 years ago
Ananya Sharma
36 Points
8 years ago
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