Using the law of conservation of angular momentum, we have
<span>I1 w1 = I2 w2 </span>
<span>ie., m1r^2/2 x w1 = ( m1r^2/2 + m2r^2 ) w2 </span>
<span>ie., new angular velocity w2 = m1 w1 / ( m1+ 2m2) = 125 x 3.1 / ( 125 + 2 x39.5 ) </span>
<span>= 1.8995 = 1.9 rad /sec ( nearly )</span>
a) KE=energy required to make them move=1800J
b) KE=1/2*mv^2, so 
J
<span>The loudness of the sound increases gradually as the air is slowly introduced in to the jar. This is because sound needs a physical medium and in a vacuum there is none. The air provides that medium and as it is introduced, the transfer of sound energy increases</span>
Momentum has both direction and magnitude.
It is a vector quantity.
Its formula is = Mass * Velocity, Mass you know is associated with size and velocity of course is associated with direction.
C. direction and magnitude
when we need to represent the magnetic field in a specific region where it is given that magnetic field lines are perpendicular to the plane and going inside the plane then we always use the concept of representation by "X"
here this symbol represents that field lines are going into the plane
it is also the uniform magnetic field always
so the correct answer would be
<u>Magnetic Field</u>
