Answer:
0.68 s
Explanation:
We are given that
Initial velocity of box=
Final velocity of box=v=11.5 m/s
Distance=d=8.5 m
We have to find the time taken by box to slow by this amount.
We know that

Substitute the values




We know that
Acceleration=
Substitute the values



Hence, the time taken by box to slow by this amount=0.68 s
Answer: The statement "The charge cannot be created or destroyed describes the principle of the conservation of charge".
Explanation:
According to the conservation of charge, the charge can neither be created nor destroyed. It can be transferred from one system to another.
In an isolated system, the total electric charge remains constant. The net quantity of electric charge is always conserved in the universe.
Therefore, "the charge cannot be created or destroyed" describes the principle of the conservation of charge.
Answer:
b. Friction decreased when he went from pavement to ice and then increased two more times.
Explanation:
Frictional force depends on the normal force of the surface and a friction coefficient.

Since we're talking about the same car, the value of
will remain constant whereas μ will represent the change in the frictional coefficient of the surface. Now we consider the different surfaces, cars will slide in an icy road which means that the frictional coefficient is smaller than the pavement.
After Joshua returns to the pavement road, the resulting frictional force increases and will do so one more time when he reaches the gravel road. Gravel roads have greater frictional coefficients than pavement roads which means the frictional force will increase a second time.
To solve this problem it is necessary to apply the concepts related to mutual inductance in a solenoid.
This definition is described in the following equation as,

Where,
permeability of free space
Number of turns in solenoid 1
Number of turns in solenoid 2
Cross sectional area of solenoid
l = Length of the solenoid
Part A )
Our values are given as,





Substituting,



PART B) Considering that many of the variables remain unchanged in the second solenoid, such as the increase in the radius or magnetic field, we can conclude that mutual inducantia will appear the same.