Suppose you have two magnets. Magnet A doesn't have its poles labeled, but Magnet B does have a clearly labeled north and south
2 answers:
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Answer:
The rate of the boat in still water is 44 mph and the rate of the current is 4 mph
Explanation:
x = the rate of the boat in still water
y = the rate of the current.
Distance travelled = 120 mi
Time taken upstream = 3 hr
Time taken downstream = 2.5 hr
Speed = Distance / Time
Speed upstream
Speed downstream
Adding both the equations
The rate of the boat in still water is <u>44 mph</u> and the rate of the current is <u>4 mph</u>
These are actually 4 different exercises:
ex 1) The sailboat moves north, while the wind moves from southeast. This means the angle between the direction of the boat and the wind is
.
Calling F the force of the wind, and
the distance covered by the boat, the work done by the wind is:
The total time of the motion is
and therefore the power of the wind is
ex 2) First of all, let's calculate the length of the ramp. Given the two sizes 2.00 m and 6.00 m, we have
The mechanical advantage (MA) of the ramp is the ratio between the output load (W) and the input force (F). The output load is the weight of the load, mg, therefore:
Finally, the efficiency
of the ramp is the ratio between the output energy and the work done. The output energy is simply the potential energy (Ep) of the load, which is mgh, where h is the height of the ramp. The work done W is the product between the input force, F, and the displacement of the load, which is the length of the ramp: Fd. Therefore:
ex 3) the graph is missing
ex 4) We know that the power is the ratio between the work done W and the time t:
But we can rewrite the work as
where F is the force applied, d the displacement of rock and![\theta=60^{\circ]](https://tex.z-dn.net/?f=%5Ctheta%3D60%5E%7B%5Ccirc%5D)
is the angle between the direction of the force and the displacement (3 m).
Therefore we can rewrite the power as
where
is the velocity, Using the data of the exercise, we can then find the force, F:
and now we can also calculate the work, which is
ex 1) The sailboat moves north, while the wind moves from southeast. This means the angle between the direction of the boat and the wind is
Calling F the force of the wind, and
The total time of the motion is
ex 2) First of all, let's calculate the length of the ramp. Given the two sizes 2.00 m and 6.00 m, we have
The mechanical advantage (MA) of the ramp is the ratio between the output load (W) and the input force (F). The output load is the weight of the load, mg, therefore:
Finally, the efficiency
ex 3) the graph is missing
ex 4) We know that the power is the ratio between the work done W and the time t:
But we can rewrite the work as
where F is the force applied, d the displacement of rock and
Therefore we can rewrite the power as
where
and now we can also calculate the work, which is