Answer:
400 N
Explanation:
By the law of friction,
is the maximum frictional force, 
is the coefficient of friction and 
is the reaction on the refrigerator. On a horizontal surface, the reaction is equal to the weight of the refrigerator.
While not moving, the fricition on the refrigerator is static friction. So, 
This is the maximum frictional force and is more than the applied horizontal force of 400 N. Frictional force cannot be more than the applied force, else it would actually pull the refrigerator backwards (a strange thing, if it were to happen). It is equal to the extent of the applied force because the applied force is not enough to overcome the maximum.
Hence the frictional force is 400 N.
PS: Note that we do not use the coefficient of kinetic friction because applied force could not overcome the static friction.
Answer:
C
Explanation:
V=1/p
By means of cross multiplication so by that we will have pv=1 which also implies p1v1=p2v2 coz boyles law states that the volume of a given mass of gas is inversely proportional to pressure provided that the temperature in kelvin remains constant
Answer:
a.
b.
Explanation:
We are given that
a.We have to find the angle
b. We have to find the speed 
According to law of conservation of momentum
The EMF of the battery includes the force to to drive across its internal resistance. the total resistance:
R = internal resistance r + resistance connected rv
R = r + rv
Now find the current:
V 1= IR
I = R / V1
find the voltage at the battery terminal (which is net of internal resistance) using
V 2= IR
So the voltage at the terminal is:
V = V2 - V1
This is the potential difference vmeter measured by the voltmeter.
