Answer:
Explanation:
The refractive index of a medium is a measure to know how much the speed of light within the medium is reduced. It can be calculated with the next equation:
(1)
Where:
The speed of light in the vacuum is approximately 300,000 km/s. In order to work with the same units let's do the proper conversion with the velocity of the medium:
Finally, replacing the data in (1):
Answer:
207.4 N
Explanation:
The torque 
on a body is
where r is the radius vector from the point of rotation to the point at which force F is applied.
The product of r and F is equal to the product of magnitude of r and F multiplied by the sine of angle between both vectors.
Therefore, torque is also given by
Where 
is the angle between r and F.
Use the expression of torque.
Substitute L for r in the equation
Where L is the length of the wrench.
Making F the subject
Force required to pull the wrench is given as,
Substitute 
for , 25 cm for L, and 115o for
Consider 20 deg.C. as room temperature.
From tables,
Silver has a resistivity of 1.6*10^-8 ohm-m at 20 deg.C, and it increases by 0.0038 ohm-m per deg.K increase.
Therefore if the temperature rise above 20 deg.C is T, then silver will have resistivity of
1.6*10^-8(1 + 0.0038T) ohm-m
At room temperature, the resistivity of tungsten (from tables) is 5.6*10^-8.
The resistivity of silver will be 4 times that of tungsten (at room temperature) when
1.6*10^-8(1 + 0.0038T) = 4*5.6*10^-8
1 + 0.0038T = 14
T = 13/.0038 = 3421 deg.K approx
Answer: 20 + 3421 = 3441 °C
I am quite sure the first one is Friction, but I am not sure about the second one. Is it wind?
