System Of Particles Flashcards
Is it necessary that a mass should be present at the centre of mass of any system
No it is not necessary for Mass to be to be there at the centre of mass ring has centre of mass at its centre where there is no mass
Why are spokes provided in a bicycle wheel
The spokes of cycle wheel increase its moment of inertia. The greater the moment of inertiaThe greater is the opposition to any changes in uniform rotational motion. As a result the cycle runs smoother and steadier. If the cycle wheels has no spokes,the cycle would be driven in jerks and hence unsafe
By spinning the eggs on a table top, how will you distinguish a hard boiled egg from a raw egg
A raw egg contains liquid in it. When the raw egg is rotated on a table top, liquid in it tries to move away from the axis of rotation because of centrifugal force. Due to this moment of inertia increase and thereby it’s angular velocity decreases and comes to rest
In case of boiled egg angular velocity increases.
We cannot open or close the door by applying force at hinges. Why
Torque = Force x lever arm of force
When the force is applied at hinges, lever arm of the force will be zero. So there will be no torque and hence cannot open or close the door
Why is it easier to balance a bicycle in motion
The rotating wheels of a bicycle has angular momentum. In the absence of an external torque , neither the magnitude nor the direction of angular momentum change. The direction of angular momentum is along the axis of the wheel. So the bicycle does not get tilted
What is the difference in the position of a girl carrying a bag in one of her hands and another girl carrying the bag in each of her two hands
In the case of a girl carrying a bag in one of her hands the centre of mass of her body is shifted towards the hand in which she is carrying the bag . To balance this she will lean lean little bit in the opposite direction. In the case of a girl carrying a bag each of her two hands they will be no change in the position of her centre of mass
