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4 years ago

How could the hydraulic energy develop in the future?

1 answer:

8 0

The US Department of Energy has set its own targets to achieve 15% of the country's electricity from hydropower by 2030 — it is currently 7%. Elsewhere around the world, countries are pledging to meet more and more of their energy needs through renewable energy sources.

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Electrons moving back and forth through a circuit would be

yaroslaw [1]

The particles that carry charge through wires in a circuit are mobile electrons. The electric field direction within a circuit is by definition the direction that positive test charges are pushed. Thus, these negatively charged electrons move in the direction opposite the electric field.

5 0

4 years ago

If a ball is thrown vertically upward from the roof of 32 foot building with a velocity of 64 ft/sec, its height after t seconds

stepan [7]

Answer:

a) $s_{max} = 96\,ft$ , b) $v(4.449\,s) = -78.368\,\frac{ft}{s}$

Explanation:

a) The maximum height is obtained with the help of the First and Second Derivative Tests:

First Derivative

$v(t) = 64 - 32\cdot t$

$64 - 32\cdot t = 0$

$t = 2\,s$

Second Derivative

$a(t) = -32$ (absolute maximum)

The maximum height reached by the ball is:

$s (2\,s) = 32 + 64\cdot (2\,s) - 16\cdot (2\,s)^{2}$

$s_{max} = 96\,ft$

b) The time required by the ball to hit the ground is:

$32+64\cdot t - 16\cdot t^{2} = 0$

$-16\cdot (t^{2}-4\cdot t - 2) = 0$

$t^{2}-4\cdot t - 2 = 0$

$(t -4.449)\cdot (t+0.449)\approx 0$

Just one root offers a solution that is physically reasonable:

$t = 4.449\,s$

The velocity of the ball when it hits the ground is:

$v(4.449\,s) = 64 - 32\cdot (4.449\,s)$

$v(4.449\,s) = -78.368\,\frac{ft}{s}$

6 0

3 years ago

Read 2 more answers

A penny rides on top of a piston as it undergoes vertical simple harmonic motion with an amplitude of 4.0cm. If the frequency is

nadezda [96]

Answer:

in the downward movement of the movement when the constant is lost

Explanation:

When the coin is on the piston it has a relationship given by

a = d²x / dt²

the piston position is

x = A cos wt

a = - A w² cos wt

the maximum acceleration is

a = - A w²

When the piston raises the acceleration of gravity and that of the piston go in the same direction, when the piston descends they relate it is contrary to gravity, therefore when the frequency increases, the point where the acceleration of the piston is greater than gravity arrives and the coin loses contact.

The point where you lose contact is

a = g

g = A w²

In short, in the downward movement of the movement when the constant is lost

7 0

3 years ago

This problem has been solved!

RideAnS [48]

Answer:

Option (a)

Explanation:

We will discard options that don't fit the situation:

Option b: Incorrect since if the driver "hits the gas" then velocity is augmenting and it's not constant.

Option c and d: Incorrect since the situation doesn't give us any information that could be related directly to the terrain or movement direction.

Option a: Correct. At stage 1 we can assume the driver was going at constant speed which means acceleration is constantly zero. At stage 2 we can assume the driver augmented speed linearly, this is, with constant positive acceleration. At stage 3 we can assume the driver slowed the speed linearly, with constant negative acceleration.

6 0

3 years ago

Describe your motion in terms of velocity and acceleration as you ride in a car down the street, come to a red light, wait for t

aleksandr82 [10.1K]

Ride in a car down the street: constant velocity,
come to a red light: negative acceleration,
wait for the green light: zero velocity,
start off again: positive acceleration

7 0

3 years ago

Read 2 more answers