Chapter #5 :Torque ,Equilibrium and Angular Momentum (Circular Motion) : Short Q/A / C.R.Q's

Q. Why does a long bar helps a tight rope walker to keep his balance?
Ans. It works on the principle of moment. is the second condition of equilibrium. When sum of the torques acting on a body is equal to zero the body is said to be in equilibrium. The rope walker adjusts the amount of torque by increasing or decreasing the length of the bar on either side of the rope so it will help him to be in equilibrium.

Q. When the divers and acrobats wishes to make several somersaults, they pull their hands towards body. Why?
Ans. When divers and acrobats wish to make several somersaults they pull their hands close to the body in order to rotate at higher rates. Due to close distribution of masses the moment of inertia decreases. This causes an increase in the angular velocity enabling them to make several somersaults.

Q. Is the normal force on the tyres of car is equal?
Ans. No. The normal force on the tyres is equal because the position of the engine shifts the center of mass of anybody. So the normal force on the tyres on the front side (because normally the engine is at the front side) has the grater normal force because they are close to the centre of mass.

Q. Why do you keep your legs apart when you have to stand in the aisle of a bumpy-riding bus?
Ans. It works on the principle of moment. is the second condition of equilibrium. When sum of the torques acting on a body is equal to zero the body is said to be in equilibrium. So by keeping the legs apart we Increases the moment of inertia and decrease the angular velocity it will help us in  order to continue our state and avoiding the falling.

Q. You are falling of the edge, What should you do to avoid falling?
Ans. In order to avoid falling we adjust our body in such a manner that the center of our mass should be in lined with the surface we are standing by doing this we can avoid falling of the edge. For this we moves our body forward and backward to find a point where our body  becomes in equilibrium.

COMMON COLLECTOR CONFIGURATION OF A TRANSISTOR

COMMON COLLECTOR CONNECTION

In  this  configuration  the  input  is  applied  between the  base  and  the  collector and  the  output  is  taken  from  the  collector  and  the  emitter.  Here  the  collector  is common to both the input and the output circuits as shown in Fig.

Common Collector Transistor Circuit

In  common  collector  configuration  the  input  current  is  the  base current  IB  and  the output current is the emitter current IE. The ratio of change in emitter current to the  change in the base current is called current amplification factor.

It is represented by

COMMON COLLECTOR CIRCUIT

A test  circuit  for determining the  static characteristic  of an NPN transistor is shown in Fig. In this circuit the collector is common to both the input and the output circuits.   To   measure   the   base   and   the   emitter   currents,   milli   ammeters   are connected in series with the base and the emitter circuits. Voltmeters are connected   across the input an…