The average velocity of Sandy is given by the total distance covered S divided by the total time taken t:
The total distance covered is
while the total time taken is 2 hours + half an hour (for the rest) + 1 hour and half, so
Therefore, the average velocity is
Answer:
v = 2 v₁ v₂ / (v₁ + v₂)
Explanation:
The body travels the first half of the distance with velocity v₁. The time it takes is:
t₁ = (d/2) / v₁
t₁ = d / (2v₁)
Similarly, the body travels the second half with velocity v₂, so the time is:
t₂ = (d/2) / v₂
t₂ = d / (2v₂)
The average velocity is the total displacement over total time:
v = d / t
v = d / (t₁ + t₂)
v = d / (d / (2v₁) + d / (2v₂))
v = d / (d/2 (1/v₁ + 1/v₂))
v = 2 / (1/v₁ + 1/v₂)
v = 2 / ((v₁ + v₂) / (v₁ v₂))
v = 2 v₁ v₂ / (v₁ + v₂)
Nitrogen isotopes don't have a charge.
1) First of all, let's find the resistance of the wire by using Ohm's law:
where V is the potential difference applied on the wire, I the current and R the resistance. For the resistor in the problem we have:
2) Now that we have the value of the resistance, we can find the resistivity of the wire
by using the following relationship:
Where A is the cross-sectional area of the wire and L its length.
We already have its length
, while we need to calculate the area A starting from the radius:
And now we can find the resistivity:
