00:01
Question number one is related to roller poster.
00:05
Here, the distance is 3 into 10 raised to 2 meter.
00:14
And work done is equal to 2 .13 into 10 .6 jule.
00:24
Then we need to find out the force.
00:27
Now we know that work done is equal to force into displacement into the cosine of angle between them.
00:39
In this case, theta is zero.
00:42
So cost theta is one.
00:46
So work done is equal to force into displacement.
00:52
It means force is equal to work upon displacement 2 .13.
01:01
Into 10 raise to 6 is the work and displacement is 3 into 10 to 2 forces 4 says 7 .1 into 10 raise to 3 neuter this is the answer for 1 now we go to part 2 is the construction crane problem here distance is 76 .2 meter work done is equal to 1 .31 into 10 rest to 3 jule.
01:57
So force is equal to work done upon distance 1 .31 into 10 rest to 3 divided by 76 .2, which is 17 .19, newton.
02:20
So force is 17 .19 newton.
02:27
This is the answer for part two.
02:37
Now we come to question number three.
02:42
Here, when the object is lifted directly, the distance is 1 .5 meter, the vertical distance.
02:54
And work done is 1 ,800 jule.
02:59
So force in the first case is equal to work done upon the distance which is 1800 divided by 1 .5 is 1200 newton.
03:21
In the second case when object is raised over a slanting platform, right? this we can call it a slanting platform and its height is 1 .5 meter.
03:39
It raises to the same height but not directly.
03:45
This is 1 .5 meter, right? and here the length of the slanting platform is 5 meter.
04:00
So in this case, the object rises to the same.
04:04
Vertical height but it travels more distance rather than 1 .5 meter it travels now 5 meter it travels by 5 meter right so in second case we can say the distance is equal to 5 meter and work done is same in both the cases right so we can say the force in second case is equal to 1 ,800 divided by 5 which means 360 newton.
04:51
So if we push an object on the slanting platform to the same height, then we need less force 360 newton as compared to when we lift it vertically up.
05:06
So this is the answer for third question.
05:09
F1 is 1200 newton in first case when it is vertically up.
05:14
And f2 when it is on the slanting platform is 360 newton this is the answer for the question number three right now we go to question number four question number four is the sunken means treasure problem now here mass is given as 2140 kilogram and the depth is given as 17 meter and once we attach the air bladders to the mass sunken treasure after uh means uh means attaching the air blaser we still have to do a work of 4 .27 into 10 raise to 3 joules to means bring it means bring it out of the water now the question is that if suppose this is the water level this is the water level right suppose this is the water level and the treasure is here somewhere so when we attach suppose the no air bladders are not attached to it then we have to apply upward force nearly equal to its weight it will be little more than the weight say because we also so, it means resist the weight of the water above it, but it will be nearly equal to its weight mg.
06:58
Right.
06:59
But when we attach the air bladders, means sort of hair balloons, which can be in, means flattened inside the water.
07:12
So these balloons means provide a force of buoyancy.
07:16
So suppose u is the force of buoyancy.
07:23
So by attaching the air balloons, the effective weight of the balloon is now its actual weight minus force of buoyancy.
07:35
So as the weight is reduced, now we have to apply less force.
07:40
So this is the value of the force we want to calculate.
07:44
And if force is less and we are moving with a distance of 17 minutes.
07:49
We have to do some work, still have to do some work.
07:53
Because if force is biancy is high, if the air bladders are of large size, then it will automatically move up to the surface of the water.
08:05
So here we can say we still have to do some work to move it by a distance of 17 meter.
08:14
So we have to still apply some force.
08:16
But this force is less than the force which we have to apply if there are not.
08:20
No air bladder attached to it because in that case its mass will be more.
08:26
So force here will be simply we know it is work upon distance, right? so 4 .27 10 raise to 3 distance is 17 meter.
08:41
So it comes out to be 251 .18 newton.
08:49
Right? this is the force.
08:50
We need to apply.
08:55
This is question number four.
09:01
Now we will come to question number five, which is a problem of sliding down of a range on an inclined plane.
09:13
So as it slides down with constant with zero acceleration, it's slide down with constant velocity.
09:23
Constant velocity means acceleration is zero.
09:27
Constant velocity means acceleration is zero.
09:34
Acceleration is zero...