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2 years ago

How can citizens affect environmental policy at the local, state, and national levels

1 answer:

3 0

You can send in a letter or request to change or enforce a policy. You can also protest or elect officials that agree with you.

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Consider the same roller coaster. It starts at a height of 40.0 m but once released, it can only reach a height of 25.0 m above

poizon [28]

Answer:

The magnitude of the frictional force between the car and the track is 367.763 N.

Explanation:

The roller coster has an initial gravitational potential energy, which is partially dissipated by friction and final gravitational potential energy is less. According to the Principle of Energy Conservation and Work-Energy Theorem, the motion of roller coster is represented by the following expression:

$U_{g,1} = U_{g,2} + W_{dis}$

Where:

$U_{g,1}$ , $U_{g,2}$ - Initial and final gravitational potential energy, measured in joules.

$W_{dis}$ - Dissipated work due to friction, measured in joules.

Gravitational potential energy is described by the following formula:

$U = m \cdot g \cdot y$

Where:

$m$ - Mass, measured in kilograms.

$g$ - Gravitational constant, measured in meters per square second.

$y$ - Height with respect to reference point, measured in meters.

In addition, dissipated work due to friction is:

$W_{dis} = f \cdot \Delta s$

Where:

$f$ - Friction force, measured in newtons.

$\Delta s$ - Travelled distance, measured in meters.

Now, the energy equation is expanded and frictional force is cleared:

$m \cdot g \cdot (y_{1} - y_{2}) = f\cdot \Delta s$

$f = \frac{m \cdot g \cdot (y_{1}-y_{2})}{\Delta s}$

If $m = 1000\,kg$ , $g = 9.807\,\frac{m}{s^{2}}$ , $y_{1} = 40\,m$ , $y_{2} = 25\,m$ and $\Delta s = 400\,m$ , then:

$f = \frac{(1000\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (40\,m-25\,m)}{400\,m}$

$f = 367.763\,N$

The magnitude of the frictional force between the car and the track is 367.763 N.

7 0

3 years ago

Aconstant current of 3 Afor 4 hours is required to charge an automotive battery. If the terminal voltage is V, where t is in hou

kirza4 [7]

Answer:

(a) 43.2 kC

(b) 0.012V kWh

(c) 0.108V cents

Explanation:

Given:

i = current flow = 3 A
t = time interval for which the current flow = $4\ h = 4\times 3600\ s = 14400\ s$
V = terminal voltage of the battery
R = rate of energy = 9 cents/kWh

Assume:

Q = charge transported as a result of charging
E = energy expended
C = cost of charging

Part (a):

We know that the charge flow rate is the electric current flow through a wire.

$\therefore i = \dfrac{Q}{t}\\\Rightarrow Q =it\\\Rightarrow Q = 3\times 14400\\\Rightarrow Q = 43200\ C\\\Rightarrow Q = 43.200\ kC\\$

Hence, 43.2 kC of charge is transported as a result of charging.

Part (b):

We know the electrical energy dissipated due to current flow across a voltage drop for a time interval is given by:

$E = Vit\\\Rightarrow E = V\times 3\times 4\\\Rightarrow E = 12V\ Wh\\\Rightarrow E = 0.012V\ kWh\\$

Hence, 0.012V kWh is expended in charging the battery.

Part (c):

We know that the energy cost is equal to the product of energy expended and the rate of energy.

$\therefore \textrm{Cost}=\textrm{Energy}\times \textrm{Rate}\\\Rightarrow C = ER\\\Rightarrow C = 0.012V\times 9\\\Rightarrow C =0.108V\ cents$

Hence, 0.108V cents is the charging cost of the battery.

4 0

3 years ago

You kick a ball with a speed of 14 m/s at an angle of 51 degrees. How far away does the ball land?

zvonat [6]

D may be the correct answer because speed is very low so ball should cover less distance but angle is not very high so it can cover little much distance

5 0

3 years ago

Read 2 more answers

Calculate the heat gained by 125.0 g of water when it is put into a calorimeter and its

jeka94

Answer:

I don't know I'm sorry I will tell you another answer asks me

4 0

2 years ago

A weight lifter bench‑presses a 160.0 kg 160.0 kg barbell from his chest to a height equal the length of his arms, 0.800 m . 0.8

Vaselesa [24]

Answer:

A. 1254.4 J

B. 1254.4 J

C. 43904 calories

Explanation:

Parameters given:

Mass of barbell, m = 160 kg

Length of arm, d = 0.8

A. Work done by weight lifter in lifting the barbell is:

W = F * d

Where F is force

F = m * g

=> W = m * g * d

W = 160 * 9.8 *0.8

W = 1254.4 J

B. Potential energy is given as:

PE = m * g * h

Where h is height (in this case, D)

=> PE = m * g * d

PE = 160 * 9.8 * 0.8

PE = 1254.4 J

C. The number of calories the weight lifter uses after lifting the barbell 35 times is equal to 35 times the potential energy, since a calorie is the measure of the amount of potential energy a piece of food contains:

35 * 1254.4 = 43904 calories.

5 0

3 years ago