Related Questions

A semicircular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi circular disc and horizontal surface is µ. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will
A Remain horizontal
B Slant up towards direction of pull
C Slant down towards direction of pull
D None of the above
A disc is a spinning with an angular velocity $$\omega $$ rad/s about the axis of spin. The couple applied to the disc causing precession will be (where $$I$$ = Mass moment of inertia of the disc and $$\omega {\text{P}}$$  = Angular velocity of precession of the axis of spin)
A $$\frac{1}{2}I{\omega ^2}$$
B $$I{\omega ^2}$$
C $$\frac{1}{2}I\omega \omega {\text{P}}$$
D $$I\omega \omega {\text{P}}$$
A circular disc rotates at n rpm. The angular velocity of a circular ring of same mass and radius as the disc and to have the same angular momentum is
A n rpm
B $$\frac{{\text{n}}}{2}$$ rpm
C $$\frac{{\text{n}}}{4}$$ rpm
D 2n rpm
If 2 kg of metal, of which 1/3 is zine and the rest is copper , be mixed with 3 kg of metal, of which 1/4 is zinc and the rest is copper , then what will be the ratio of zinc to copper in the mixture?
A 17 : 43
B 13 : 42
C 19 : 43
D 15 : 42
If 2 kg of metal, of which 1/3 is zinc and the rest is copper s, be mixed with 3 kg of metal , of which 1/4 is zinc and the rest is copper , then what will be the ratio of zinc to copper in the mixture?
A 13 : 42
B 19 : 43
C 15 : 42
D 17 : 43
It is difficult to fix a nail on a freely suspended wooden frame. Which law supports this statement?
A Law of inertia
B Newton's second law
C Newton's third law
D Pascal's law
What should a person on a freely rotating turn table do to decrease his (angular) speed ?
A Bring his hands together
B Raise his hands up
C Spread his hands outwards
D Sit down with raised hands
The length of the needle beam used in needle beam method of tunnelling is usually
A 2 m to 4 m
B 2.5 m to 6 m
C 4 m to 7 m
D 5 m to 6 m
The moment of inertia of a thin disc of mass ‘m’ and radius ‘r’, about an axis through its center of gravity and perpendicular to the plane of the disc is
A $$\frac{{{\text{m}}{{\text{r}}^2}}}{2}$$
B $$\frac{{{\text{m}}{{\text{r}}^2}}}{4}$$
C $$\frac{{{\text{m}}{{\text{r}}^2}}}{6}$$
D $$\frac{{{\text{m}}{{\text{r}}^2}}}{8}$$
How does the magnetic compass needle behave in a magnetic field?
A It assures a position right angle to magnetic field
B It starts rotating
C It assures a position which follows a line of magnetic flux
D None of the above

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