All categories

3 years ago

Which of the following represents a system that is completely open?

Physics

2 answers:

Bezzdna [24]3 years ago

6 0

Answer:

I choose D

Explanation:

because all of the other ones are most likey to be close/coverd

fredd [130]3 years ago

5 0

<span>The correct answer is D. The system that is completely open of the available answers would be an open pot of boiling water. This is due to the fact that an open system is defined as one in which energy or mass can be put out into or taken from the environment. Therefore, the evaporation of water due to the heat when a pot is boiling would be an example of lost energy, and therefore this is an open system.</span>

You might be interested in

30 points! Please answer at least one and how you found it! :)

const2013 [10]

1 Is advantage because with out is. you couldn't carry the piano at all.
2 Efficiency because it is going against you.

6 0

3 years ago

Even when the head is held erect, as in the figure below, its center of mass is not directly over the principal point of support

alexandr1967 [171]

We are asked to determine the force required by the neck muscle in order to keep the head in equilibrium. To do that we will add the torques produced by the muscle force and the weight of the head. We will use torque in the clockwise direction to be negative, therefore, we have:

$\Sigma T=r_{M\perp}(F_M)-r_{W\perp}(W)$

Since we want to determine the forces when the system is at equilibrium this means that the total sum of torque is zero:

$r_{M\perp}(F_M)-r_{W\perp}(W)=0$

Now, we solve for the force of the muscle. First, we add the torque of the weight to both sides:

$r_{M\perp}(F_M)=r_{W\perp}(W)$

Now, we divide by the distance of the muscle:

$(F_M)=\frac{r_{W\perp}(W)}{r_{M\perp}}$

Now, we substitute the values:

$F_M=\frac{(2.4cm)(50N)}{5.1cm}$

Now, we solve the operations:

$F_M=23.53N$

Therefore, the force exerted by the muscles is 23.53 Newtons.

Part B. To determine the force on the pivot we will add the forces we add the vertical forces:

$\Sigma F_v=F_j-F_M-W$

Since there is no vertical movement the sum of vertical forces is zero:

$F_j-F_M-W=0$

Now, we add the force of the muscle and the weight to both sides to solve for the force on the pivot:

$F_j=F_M+W$

Now, we plug in the values:

$F_j=23.53N+50N$

Solving the operations:

$F_j=73.53N$

Therefore, the force is 73.53 Newtons.

8 0

11 months ago

Which of the following are inertial reference frames? A. A car driving at steady speed on a straight and level road. B. A car dr

Aloiza [94]

Answers:

A. A car driving at steady speed on a straight and level road.

B. A car driving at steady speed up a 10∘ incline.

Explanation:

An object is said to be in an inertial reference frame if the net force acting on the object is zero. According to Newton's second law, this also means that the acceleration of the object is also zero:

$F=ma$

Since F=0, a=0 as well.

Let's now analyze each case.

A. A car driving at steady speed on a straight and level road. --> YES: this is an inertial reference frame, because the car is keeping a constant speed and a constant direction, so its velocity is not changing, and its acceleration is zero.

B. A car driving at steady speed up a 10∘ incline. --> YES: this is an inertial reference frame, because the car is keeping a constant speed and a constant direction, so its velocity is not changing, and its acceleration is zero.

C. A car speeding up after leaving a stop sign. --> NO: this is not an intertial reference frame, because the car is speeding up, so it is accelerating.

D. A car driving at steady speed around a curve. --> NO: this is not an inertial reference frame, because the car is changing direction, therefore its velocity is changing and so the car is accelerating.

So the only two choices which are correct are A and B.

8 0

3 years ago

Read 2 more answers

Why won't a very bright beam of red light impart more energy to an ejected electron than a feeble beam of violet light?

bearhunter [10]

This is related to the energy carried by photons of light the energy of each photon is proportional to the frequency of the light since red light has a lower frequency then violet light and photons of red light carry less energy than the photons of violet light as a result the red protons eject electrons that have less energy than the ejected electrons by Violet photons

3 0

3 years ago

Why does the entropy of a gas increase when it expands into a vacuum? Why does the entropy of a gas increase when it expands int

Mrrafil [7]

Answer:

The entropy of a gas increases when it expands into a vacuum because the number of possible states increases .

Explanation:

When a gas expand in a vacuum, the molecules of the gases vibrates very fast and starting moving with higher velocity in random directions which means the level of disorder in the gases increases.

Now the possible state of the gas molecule increases such as the particle can be located at different position due to increased randomness.

<u>Entropy is the measure of this randomness and thus with this increased randomness entropy also increases.</u>

6 0

3 years ago