### Chapter #3 :Motion : Short Q/A / C.R.Q's

Q. It is observed that all bodies sliding down a frictionless inclined plane have the same acceleration. How does it happen?
Ans. The acceleration of any body sliding down the inclined plane is given by
a= g SinÎ¸
This formula is showing that the acceleration of any body is independent of the mass or radius or something else .It only depends on the value of g and the angle of inclined surface with the horizontal.

Q. Can an object has zero velocity and still have acceleration?
Ans.Yes, When a body is vibrated and it is at the extreme position its velocity is zero. But the acceleration is maximum.
Another example is that when the body is at the maximum height it has the velocity zero but has acceleration equal to g.

Q. If two spheres of different size and mass are roll down the inclined plane without friction, which will reach the down first?
Ans. The acceleration of any body sliding down the inclined plane is given by
a= g SinÎ¸
This formula is showing that the acceleration of any body is independent of the mass or radius or something else .It only depends on the value of g and the angle of inclined surface with the horizontal.

Q. If two forces are acting on a body then what is the condition that (1) The body has Constant Velocity (2) Constant Speed
Ans.If two forces are acting on a body and their resultant is non zero then it has acceleration and the change in velocity is due to the change in direction with constant speed i.e. in the circular motion. And if the resultant of two forces is equal to zero then the body has constant velocity

Q. Does the speed of a body be negative?
Ans. No, Speed is a scalar quantity .Or it only represents the magnitude but not the direction so speed can never be a negative quantity.

Q. What is the acceleration of the bodies with masses 10Kg and 20Kg while they are dropped from same height?
Ans. During free fall motion the acceleration of a body becomes equal to the acceleration due to gravity and it does not depends on the mass it only depends on the height so if two bodies are falling from same height so both will have the same acceleration.

### 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…