CBSE 11TH PHYSICS - Online Test
if L = const.
then
When a dancer is spinning, she has a certain angular momentum. When the dancer folds her arms, the distance of all the points of her body decreases with respect to axis of rotation so that her moment of inertia decreases. Thus, in order to conserve angular momentum, the speed of rotation has to increase and hence the dancer spins faster.
Hence if moment of inertia decrease then kinetic energy will increase.
Three vessels of equal capacity have gases at the same temperature and pressure. The first vessel contains neon (monatomic), the second contains chlorine (diatomic), and the third contains uranium hexafluoride (polyatomic). In which case is the largest?
Neon has smaller molecular wt in comparision to chlorine and uranium hexafluoride. So that is largest for neon.
on heating spring will be expand
Relative density means how much times a substance is denser than water.
Now relative density of lead = 11.3 means lead is 11.3 times denser than water.
Now water has a density 1 g cm–3 in cgs units
Thus lead will have a density = 11.3 x 1 g cm–3 = 11.3 g cm–3
Acceleration is the rate of change of velocity of an object with respect to time.
a =
SI unit of velocity = m/s
SI unit of time = s
So SI unit of acceleration =
The flag is fluttering in the north-east direction. It shows that the wind is blowing toward the north-east direction. When the ship begins sailing toward the north, the flag will move along the direction of the relative velocity (vwb) of the wind with respect to the boat.
The angle between vw and (–vb) = 90° + 45°
tan β =
Substituting and solving we get,
tan β =
∴ β = tan-1(1.0038) = 45.110
Angle with respect to the east direction = 45.11° – 45° = 0.11°
Hence, the flag will flutter approximately due east.
