Answer:
If the canoe heads upstream the speed is zero. And directly across the river is 8.48 [km/h] towards southeast
Explanation:
When the canoe moves upstream, it is moving in the opposite direction of the normal river current. Since the velocities are vector (magnitude and direction) we can sum each vector:
Vr = velocity of the river = 6[km/h}
Vc = velocity of the canoe = -6 [km/h]
We take the direction of the river as positive, therefore other velocity in the opposite direction will be negative.
Vt = Vr + Vc = 6 - 6 = 0 [km/h]
For the second question, we need to make a sketch of the canoe and we are watching this movement at a high elevation. So let's say that the canoe is located in point 0 where it is located one of the river's borders.
So we are having one movement to the right (x-direction). And the movement of the river to the south ( - y-direction).
Since the velocities are vector we can sum each vector, so using the Pythagoras theorem we have:
![Vt = \sqrt{(6)^{2} +(-6)^{2} } \\Vt=8.48[km/h]](https://tex.z-dn.net/?f=Vt%20%3D%20%5Csqrt%7B%286%29%5E%7B2%7D%20%2B%28-6%29%5E%7B2%7D%20%7D%20%5C%5CVt%3D8.48%5Bkm%2Fh%5D)
Answer:
The steps are outlined in the explanation below.
Explanation:
The average velocity is derived midpoint from the initial to the final velocity. Here is the proof:
Find the total displacement:
let the displacement be given by the letter s
Then since the average velocity is defined as: 
where t = final time
t₀ = initial time
v = final speed
v₀ = initial time
where x denotes the position, then
where v = 
and dx = change in distance with respect to time.
Answer:
electrons
Explanation:
An electric current is said to exist when there is a net flow of electric charge through a region. In electric circuits this charge is often carried by electrons moving through a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in an ionized gas (plasma).
Answer:
dT(t)/dt = k[T5 - T(t)]
Explanation:
Since T(t) represents the temperature of the object and T5 represents the temperature of the surroundings, according to Newton's law of cooling, the rate at which an object's temperature changes is directly proportional to the difference in temperature between the object and the surrounding medium, that is dT(t)/dt ∝ T5 - T(t)
Introducing the constant of proportionality
dT(t)/dt = k[T5 - T(t)]
which is the desired differential equation
The efficiency of an ideal Carnot heat engine can be written as:
where
is the temperature of the cold region
is the temperature of the hot region
For the engine in our problem, we have
and
, so the efficiency is
