When you hold a spinning wheel, the wheel and you, chair included, form a system that obeys the principle of "conservation of angular momentum". This means that any changes in angular momentum within the system must accompanied by an equal and opposite change, so the net force is zero.
Superconductor, conductor, semiconductor, insulator
Hi Pupil Here is your answer ::
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1 The shape of the Body
Example : The shape of the ball lying on a floor can be changed by pressing it.
2 Direction of the Body
Example : The direction of motion of moving ball can be changed by hitting it with a bat.
3 The speed of the Body
Example : A ball at rest can be set in motion if force is applied only
4. Size of the Body
Example : The length of a spring tied and on one end can be increased by pulling it.
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Hope this helps .......
Answer:
No, not necessarily
Explanation:
If an object is moving with an acceleration that causes its speed to be reduced, there will be a moment in which it reaches v = 0, but this doesn't necessarily mean that the acceleration isn't acting anymore. If the object continues its movement with the same acceleration, it's velocity will become negative.
An example of an object that has zero velocity but non-zero acceleration:
If you throw an object in the air with a certain velocity, it will move vertically, reducing its velocity in a 9,8 
rate (which is the acceleration caused by gravity). At a certain point, the object will reach its maximum height, and will start to fall. In the exact moment that it reaches the maximum height, before it starts falling, its velocity is zero, but gravity is still acting on the object (this is the reason why it starts falling instead of just being stopped at that point). Therefore, at that point, the object has zero velocity but an acceleration of 9,8 .
Answer:
Explanation:
Diffraction grating is used to form interference pattern of dark and bright band.
Distance between adjacent slits (a ) = 1 / 420 mm
= 2.38 x 10⁻³ mm
2.38 x 10⁻⁶ m
wave length of red light
= 680 x 10⁻⁹ m
For bright red band
position x on the screen
= n λD / a , n = 0,1,2,3 etc
D = distance of screen
putting n = 1 , 2 and 3 , we can get three locations of bright red band.
x₁ = λD / a
= 680 x 10⁻⁹ x 2.8 / 2.38 x 10⁻⁶
= .8 m
= 80 cm
Position of second bright band
= 2 λD / a
= 2 x 80
= 160 cm
Position of third bright band
= 3 λD / a
= 3 x 80
= 240 cm
