An object having mass = 2kg experience a force in x - direction. Find work done by force in first 3 sec.
Given, m = 2 kg
F = 2t^2 i
a = F/m = 2t^2/2 = t^2 i
Assuming initial velocity was zero, u = 0
We know that, dw = F.dx
Put t = 3 secs
W = 81 J
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4. 15.8m
Maximum height will be attained when the final velocity will become zero.
View Full Answer(1)A sonometer wire of length 1.5 m is made of steel. The tension in it produces an elastic strain of 1%. What is the fundamental frequency of steel if density and elasticity of steel are respectively ?
770 Hz
188.5 Hz
178.2 Hz
200.5 Hz
As we have learned
Young Modulus -
Ratio of normal stress to longitudnal strain
it denoted by Y
- wherein
F - applied force
A - Area
- Change in lenght
l - original length
Fundamental frequency
Option 1)
770 Hz
Option 2)
188.5 Hz
Option 3)
178.2 Hz
Option 4)
200.5 Hz
View Full Answer(1)Which of the following is not based on the principle of capillarity
Floating of wood on eater surface
Ploughing of soil
Rise of oil in wick of lantern
Soaking of ink by bloating paper
As we discussed in concept
Capillary -
If a tube of very narrow bore is dipped in a liquid, the liquid in the capillary either ascends or descends .
- wherein
A towel soaks water.
Floating of wood on eater surface
Option 1)
Floating of wood on eater surface
Option is correct
Option 2)
Ploughing of soil
Option is incorrect
Option 3)
Rise of oil in wick of lantern
Option is incorrect
Option 4)
Soaking of ink by bloating paper
Option is incorrect
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When the angle of contact between a solid and a liquid is 90°, then
Cohesive force > Adhesive force
Cohesive force < Adhesive force
Cohesive force = Adhesive force
Cohesive force >> Adhesive force
As we discussed in concept
Cause of viscosity -
Cause of viscosity in liquids is cohesive
-
Cohesive force = Adhesive force
Option 1)
Cohesive force > Adhesive force
Option is incorrect
Option 2)
Cohesive force < Adhesive force
Option is incorrect
Option 3)
Cohesive force = Adhesive force
Option is correct
Option 4)
Cohesive force >> Adhesive force
Option is incorrect
View Full Answer(1)When impurities are added to an elastic substance, its elasticity
Increases
Decreases
Becomes zero
May increase or decrease
As we discussed in concept
Elasticity -
That body which regain it's original shape and size
- wherein
i.e. after removal of deforming force
both way increase or decrease
Option 1)
Increases
Option is incorrect
Option 2)
Decreases
Option is incorrect
Option 3)
Becomes zero
Option is incorrect
Option 4)
May increase or decrease
Option is correct
View Full Answer(1)What is the change in surface energy, when a mercury drop of radius R splits up into 1000 droplets of radius r?
As we discussed in concept
Surface Energy -
It is defined as the amount of work done in increasing the area of the liquid against surface tension.
-
where n= 10000
After calculeting we get
Option 1)
Option is incorrect
Option 2)
Option is incorrect
Option 3)
Option is incorrect
Option 4)
Option is correct
View Full Answer(1)Water rises in a capillary tube to a certain height such that the upward force due to surface tension is balanced by 75 × 10-4 N, forces due to the weight of the liquid. If the surface tension of water is 6 × 10-2 N/m, the inner-circumference of the capillary must be
As we discussed in concept @14048
Capillary -
If a tube of very narrow bore is dipped in a liquid, the liquid in the capillary either ascends or descends .
- wherein
A towel soaks water.
Total upward force =circumference
Total upward force = weight of the liquid
Option 1)
Option is incorrect
Option 2)
Option is incorrect
Option 3)
Option is correct
Option 4)
Option is incorrect
View Full Answer(1)There is no change in the volume of a wire due to change in its length on stretching. The poison’s ration of the material of the wire is
+ .50
- 0.50
0.25
- 0.25
Strain -
Ratio of change in configuration to the original configuration.
-
Volume of wire =
Volume remain constant
Option 1)
+ .50
Incorrect
Option 2)
- 0.50
Correct
Option 3)
0.25
Incorrect
Option 4)
- 0.25
Incorrect
View Full Answer(1)There is a hole in the bottom of tank having water. If total pressure at bottom is 3 atm (1 atm = 105N/m2) then the velocity of water flowing from hole is
10 m/s
30 m/s
20 m/s
none of these
As we discussed in
Torricelli's Theorem / Velocity of Efflux -
In fluid dynamics relating the speed of fluid flowing out of an orifice.
- wherein
Gauge pressure at bottom=
Option 1)
10 m/s
Incorrect
Option 2)
30 m/s
Incorrect
Option 3)
20 m/s
Correct
Option 4)
none of these
Incorrect
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