Explanation:
The given data is as follows.
q = 6.0 nC = 
inner radius (r) = 1.0 cm = 0.01 m (as 1 cm = 100 m)
So, there will be same charge on the inner surface as the charge enclosed with an opposite sign.
Formula to calculate the charge density is as follows.
.......... (1)
Since, area of the sphere is as follows.
A =
........... (2)
Hence, substituting equation (2) in equation (1) as follows.

=
= 
or, = 4.77 
Thus, we can conclude that the resulting charge density on the inner surface of the conducting sphere is 4.77
.
ANOTHER RUNNING DOG
Explanation:
In the given question it is to find a suitable reference point to describe the motion of dog. Here I could suggest that it is better to compare the dog with another running dog to create the relative speed difference to get a reliable motion variation.
Because the motion of dog is in the linear with respect to the another dog and to the acceleration produced by the dog in the required interval is easy to calculate with respect to another dog which is already in motion.
Hence, I suggest that Motion of dog can be analysed better by analyse the motion variation of dog with another dog running.
Answer:
The object in a uniform motion covers same distances in an equal time period. Objects in a non-uniform motion cover dissimilar distances in an equal time period.
Explanation:
The speed of the object traveling in uniform motion is constant, the actual speed and the average speed of the moving body is same.
Answer:
The speed of the cart and clay after the collision is 50 cm/s .
Explanation:
Given :
Mass of lump , m = 500 g = 0.5 kg .
Velocity of lump , v = 30 cm/s .
Mass of cart , M = 1 kg .
Velocity of cart , V = 60 cm/s .
We know by conservation of momentum :

Here ,
is the speed of the cart and clay after the collision .
Putting all value in above equation .
We get :

Hence , this is the required solution .