Contact area is not a factor of the amount of friction force acting between two bodies in contact, preventing rolling or sliding
Reasons:
- Friction force is the product of the normal reaction and the coefficient of friction.
- The coefficient of friction is higher in softer tires than hard tires which are required to be wider to reduce the pressure that can cause deformation withstood by hard tires.
- The wide tires in drag racing cars can be thought of being made from the soft compound tire material having a higher coefficient of friction that increases the friction force.
Other advantages of wide tires are;
- Shorter stopping distance
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Answer:

Explanation:
For this case the situation is explained in the figure attached.
We can find the maximum radius r with the angle of incidence or critical angle (xi). If we have that the angle is higher than the light we will see a reflecting property. We can assume that the refracted angle for this case is 90 and if we use the following trigonometric property we have:

And if we solve for r we got:

The value of d on this case represent the depth of the watr d = 2.5 m
And we can find the value for the angle
using the Snell's Law like this:


And we can use the arcsin in order to find the angle like this:

And now we can find the maximum radius replacing into

And we got:

The reason why the moon does not fall back to the earth is that the Moon's rotation about its own axis creates centripetal force
that balances Earth's pull.
<h3>What is the gravitational force?</h3>
The gravitational force is the force that keeps the solar system together. All the members of the celestial bodies are help in place by gravity.
Thus, the reason that keeps the moon from falling back to the earth is because the Moon's rotation about its own axis creates centripetal force
that balances Earth's pull.
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Answer:
Electrical Conductivity is 3200 
Solution:
As per the question:

Mobility of electrons, 
Mobility of holes, 
Charge, Q = 
Now,
The formula for the conductivity is given by:

