Question

A metal plate of area 500 cm^2 is kept on a horizontal surface with a layer of castor oil of thickness 0.5 mm between them. The horizontal force required to drag for plate with a velocity of 2 cm/s is​

Answer 1

Answer:

Area A=500㎠=500×10−4㎡

Thickness dx=2㎜=2×10−3m

Co efficient of viscosity=15.5 poise=1.55pa

Velocity=3㎝s−1=3×10−2㎧

F=ηA(dxdv)

=2×10−315.5×10−1×500×3×10−4×10−2

=10−523.25×10−7

F=0.2325N

Answer 2

Explanation:

Question:

How many numbers can be obtained using 100 digits by replacing the positions of digits and not repeating?

How many numbers can be obtained using 100 digits by replacing the positions of digits and not repeating? Answer:

No. of numbers than can be obtained using 100 digits = 1×2×3×4×5×.. × 100

The product will be answer.

(you can check it, it is right.)

☆It means if the number of digits = n,

then multiply the natural numbers from 1 to n .

Hope you got it..

Try it and check.. I'll work.