409 - Physics Questions Answers
a block of mass m is pushed up a movable incline of mass nm and height h.All surfaces are smooth without friction.what must be the minimum value of u so that the block just reaches the top of the movable incline.
let velocity of m at start is u along horizontal
at the top horizontal velocity of system = u/(n+1) and vertical velocity = 0
by energy conservation 1/2 mu2 = 1/2 (nm+m) {u/(n+1)}2 + mgh
solve
A solid sphere is subjected to uniform pressure from all direction. The ratio of volumetric strain to lateral strain produced in it, is
V = 4/3 πr3
so dV = 4πr2
now calculate dV/V
What is the length of a wire whose density is 8 g/cm3, which suspended vertically, would break due to its own weight? [Breaking stress of wire is 2.4 x 108 N/m2]
use stress = force/area
When a load of 8 kg is hung on a wire, then extension of 3 cm takes place, the work done by internal forces of wire is
The work done per unit volume to stretch the length of area of cross-section 2 mm2 by 2% will be [ Y = 8 x 1010 N/m2 ]
To break a wire a stress of 9 x 105 N/m2 is required. If density of the material of wire is 3 g/cc, then the minimum length of wire which will break by its own weight will be
use stress = force /area
A steel wire is 1m long and 1mm2 in area of cross-section. If it takes 200 N to stretch this wire by 1mm, how much force will be required to stretch a wire of the same material as well as diameter from its normal length of 10m to a length of 1002 cm?
by first set of data calculate Y then by using this Y solve the question
The length of wire, when M1 is hung from it, is l1 and is l2 with both M1 and M2 hanging. The natural length of wire is [ M2 is on M1 ]
Y = M1gL/A(l1-L) = (M1+M2)gL/(l2-L)
solve for L
A nylon rope 3 cm in diameter has a breaking strength of 1.5 x 105 N. The breaking strength for a similar rope 1.5cm in diameter is
breaking stress will remain same
A cubical block of a metal having shear modulus η is fixed from one face as shown in figure and constant force F is applied on it. Find the shear strain produced in it.