Answer:
The coefficient of static friction between the puppy and the floor is 0.7273.
Explanation:
The horizontal force applied to move the puppy from a steady state has to be greater than the force of static friction, after it is moving the force needs to be equal to be greater than the force of dynamic friction in order to maintain its movement. The force of static friction is given by:

Where
is the static friction force,
is the coefficient of static friction and
is the normal force. Since there's no angle on the flor the normal force is equal to the weight of the puppy, therefore,
, to make the puppy moving we need to use a force of 80 N, therefore,
, so we can solve for the coefficient as shown below:

The coefficient of static friction between the puppy and the floor is 0.7273.
Answer:
Charge enter a 0.100 mm length of the axon is 
Explanation:
Electric field E at a point due to a point charge is given by

where
is the constant =
is the magnitude of point charge and
is the distance from the point charge
Charges entering one meter of axon is 
Charges entering 0.100 mm of axon is 
substituting the value of
in above equation, we get charge enter a 0.100 mm length of the axon is

Answer:
The boiling point of Acetone is 329K (in 3 significant figures)
Explanation:
Boiling point of Acetone = 56°C = 56 + 273K = 329K (in 3 significant figures)