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3 years ago

12

A sailboat moves north for a distance of 10.00 km when blown by a wind 30° east of south with a force of 5.00 × 104 N. How much

work was done by the wind?

1 answer:

Snowcat [4.5K]3 years ago

8 0

2.50 × 108 J 4.33 × 108 J 5.00 × 108 J 0.00 J

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A ray diagram is shown.

Rufina [12.5K]

Answer:

X

Explanation:

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3 years ago

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1. In a(n) ______________________ circuit, all parts are connected one after another along one path.

poizon [28]

Answer:

1. A <em>series circuit </em>is a closed circuit which has all loads connected in a row and there is only one path for the current to flow.

2. The <em>Ohm's Law </em>state that a current flow through a resistor is directly proportional to the voltage across it $R = \frac{V}{I}$

3. A <em>parallel circuit </em>is a closed circuit divided into branches that it has two o more paths for the current to flow and the loads are parallel to each other which mean the voltage across them is the same for all loads.

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3 years ago

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A hot air balloon is traveling vertically upward at a constant speed of 4.5 m/s. When it is 28 m above the ground, a package is

ella [17]

Answer:

1.97 seconds

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration due to gravity = 9.8 m/s²

$s=ut+\frac{1}{2}at^2\\\Rightarrow 21=4.5t+\frac{1}{2}\times -9.8\times t^2\\\Rightarrow 21=-4.5t-4.9t^2\\\Rightarrow 4.9t^2+4.5t-28=0\\\Rightarrow 49t^2+45t-280=0$

Solving the above equation we get

$t=\frac{-45+\sqrt{45^2-4\cdot \:49\left(-280\right)}}{2\cdot \:49}, \frac{-45-\sqrt{45^2-4\cdot \:49\left(-280\right)}}{2\cdot \:49}\\\Rightarrow t=1.97, -2.89$

So, the time the package was in the air is 1.97 seconds

3 0

3 years ago

A 0.29 kg particle moves in an xy plane according to x(t) = - 19 + 1 t - 3 t3 and y(t) = 20 + 7 t - 9 t2, with x and y in meters

Artist 52 [7]

Answer:

Part a)

$F = 7.76 N$

Part b)

$\theta = -137.7 degree$

Part c)

$\theta = -127.7 degree$

Explanation:

As we know that acceleration is rate of change in velocity of the object

So here we know that

$x = -19 + t - 3t^3$

$y = 20 + 7t - 9t^2$

Part a)

differentiate x and y two times with respect to time to find the acceleration

$a_x = \frac{d^2}{dt^2}(-19 + t - 3t^3)$

$a_x = \frac{d}{dt}(0 +1 - 9t^2)$

$a_x = -18t$

$a_y = \frac{d^2}{dt^2}(20 + 7t - 9t^2)$

$a_y = \frac{d}{dt}(0 +7 - 18t)$

$a_y = -18$

Now the acceleration of the object is given as

$\vec a = (-18t)\hat i + (-18)\hat j$

at t= 1.1 s we have

$\vec a = -19.8 \hat i - 18 \hat j$

now the net force of the object is given as

$\vec F = m\vec a$

$\vec F = (0.29 kg)(-19.8 \hat i - 18 \hat j)$

$\vec F = -5.74 \hat i - 5.22 \hat j$

now magnitude of the force will be

$F = \sqrt{5.74^2 + 5.22^2} = 7.76 N$

Part b)

Direction of the force is given as

$tan\theta = \frac{F_y}{F_x}$

$tan\theta = \frac{-5.22}{-5.74}$

$\theta = -137.7 degree$

Part c)

For velocity of the particle we have

$v_x = \frac{dx}[dt}$

$v_x = (0 +1 - 9t^2)$

$v_y = \frac{dy}{dt}$

$v_y = (0 +7 - 18t)$

now at t = 1.1 s

$\vec v = -9.89\hat i - 12.8 \hat j$

now the direction of the velocity is given as

$\theta = tan^{-1}(\frac{v_y}{v_x})$

$\theta = tan^{-1}(\frac{-12.8}{-9.89})$

$\theta = -127.7 degree$

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3 years ago

Identify three situations in which convection occurs

hodyreva [135]

There are three types of heat conduction through substances. These are named as conduction,convection and radiation .here we have been given convection.

Convection is the type of mode of conduction of heat in which heat will flow though a liquid and gases due to the direct physical movement of particles.In this process the hotter particles will go upward as they become lighter and cooler,heavier particles come downward which after being heated up go upward .Hence a convectional current is formed for which whole of the liquid or gas gets heated.

There are different life examples of convection.

One may take an simple example of water in a container.The water molecules which are present bottom part of the container will be heated up first and go upward.The upper particles will come downward and they will constitute a convectional current.

Another life example is the flow of wind from one region to another region.the air at hotter region will become lighter and goes upward and the wind starts flowing from cold region region in order to occupy the vacant space.

Another example is the hot air balloon rising up..It is also another example of convection of heat

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3 years ago

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