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2 years ago

This is being graded.Great answers only

Physics

1 answer:

navik [9.2K]2 years ago

6 0

Answer:

Explanation:

When a ball is at its highest point, its acceleration is 0. The only thing pulling it down, is gravity so, the correct option is D. Downwards.

I'm not sure however due to the fact that the arrows on the other options are facing backwards meaning the ball would go backwards; and for the one option the ball is going up. However, the ball isn't going backwards nor up, so it must be D. If I am wrong I greatly apologize.

You might be interested in

(a) What is the entropy change of a 14.6 g ice cube that melts completely in a bucket of water whose temperature is just above t

Alex73 [517]

Answer:

a) 17.81 J/K

b) 33.325 J/K

Explanation:

The expression to use here is the following:

ΔS = Q/T

Where:

Q: heat released or absorbed

T: Temperature in K

Now, in order to do this, we need to gather the data. We know that the temperature in part a) is above the freezing temperature of water, which is 0 ° C or 273 K. and the mass of the ice cube is 14.6 g.

a) Using the water heat of fusion (Cause it's melting), we can calculated the heat released using the following expression:

Q = m * Lf

Lf = 333,000 J/kg

Solving for Q first we have:

Q = (14.6 / 1000) * 333,000

Q = 4,861.8 J

Now, the entropy change is:

ΔS = 4,861.8 / 273

ΔS = 17.81 J/K

b) In this part, we follow the same procedure than in part a) but using the water heat of boiling (Lv = 2,256,000 J/kg), the temperature of boiling which is 100 °C (or 373 K) and the mass of 5.51 g (0.00551 kg)

Calculating the heat:

Q = 0.00551 * 2,256,000 = 12,430.56 J

Now the entropy change:

ΔS = 12,430.56 / 373

ΔS = 33.325 J/K

8 0

3 years ago

Two objects must be in contact for them to exert a force on each other. True False

Irina-Kira [14]

Answer:

False

Explanation:

The given statement "Two objects must be in contact for them to exert a force on each other" is not true as there are many types of forces that doesn't require being in contact for exerting a force.

One such example is the gravitational force acting between two bodies. Gravitational force is the force of pull with which a body pulls another body without being in contact.

For two bodies of masses 'M' and 'm' separated at a distance of 'R', the gravitational force is given as:

$Force=\frac{GMm}{R^2}\\Where,G\to \textrm{Universal Gravitational constant}$

The gravitational force acts always act between bodies that have mass. The bodies are not in contact yet experience force.

Therefore, the given statement is false.

5 0

3 years ago

A person kicks a ball off of a 50m high cliff with a speed of 10 m/s. How long will it take the ball to hit the ground? * 7 poin

Musya8 [376]

Presumably, the ball is kicked parallel to the ground below the cliff, so its altitude y at time t is

$y(t)=50\,\mathrm m-\dfrac12gt^2$

where g = 9.80 m/s^2 is the acceleration due to gravity.

The ball hits the ground when y = 0:

$0 = 50\,\mathrm m-\dfrac12gt^2$

$t^2=\dfrac{100\,\mathrm m}g$

$t=\dfrac{10}{9.80}\,\mathrm s\approx\boxed{3.2\,\mathrm s}$

6 0

3 years ago

For each of the following pairs of gas properties, describe the relationship between the properties, describe a simple system th

asambeis [7]

Answer:

For each pair of properties of a gas, the relationships are (see the explanation for the description of the systems):

(a) Volume and pressure: The relationship between them is inversely proportional.
(b) Pressure and temperature: They have a directly proportional relationship.
(c) Volume and temperature: They relationship is directly proportional.
(d) Number of gas particles and pressure: The relationship is directly proportional between them.

Explanation:

1. Volume and pressure (temperature and amount of particles constant):

They have an inversely proportional relationship, because if volume is reduced, the pressure increases, or if the volume increases, the pressure decreases.

A simple system could be one similar to the one used by Boyle to test this relationship:

Seal the short extreme of a translucent J tube. It could be glass or plastic.
Put some water on it. As much as needed to have both sides of the tube filled.
Using a syringe, and a flexible small tube,inject a determined volume of air in the bottom in a way that the bubble is trapped in the seal side of the J tube.
Then if more water is added to the tube, it will increase the pressure (from the pressure definition is possible to in the trapped air, and is possible to measure the compression of the air bubble. The same is possible if using the syringe, and the flexible tube, some water is removed, and the increasing of volume could be observed.

2. Pressure and temperature (volume and amount of particles of the gas remains constant)

They have a directly proportional relationship, because if temperature is reduced, the pressure decreases, or if the temperature increases, the pressure would increase, also.

A simple system to show this is two cans of soda.

The can is rigid, so the volume is always constant, and the amount of gas inside the soda is the same.
Put one can under the sun, and the other in the cooler.
After a while, take it out the can in the cooler, and open both cans.
The one that was under the sun will "explode", in other words, it will liberate a lot of foam of gas and soda, meaning that the pressure inside the can was high.
The one that was in te cooler, won't liberate any foam, meaning that the pressure was low.

3. Volume and temperature (pressure and amount of particles of the gas remains constant)

They have a directly proportional relationship, because if temperature is reduced, the pressure decreases, or if the temperature increases, the pressure will increase, also.

A simple system to show this is a party balloon.

Fill the party balloon with some air, not enough to be close to explode, but enough to have it of a medium size. Tie the filling hole of the balloon.

The air inside the balloon would be at the same pressure than the atmosphere around it, so always will be at this pressure, and the close hole ensure that it has always the same amount of air inside.

Now is possible to use some heat source, for example as a hair dryer to increase the temperature of the balloon and its contents. The size of the balloon will increase. Then using water is possible to cool it down and watch how its size decreases.

4. Number of gas particles and pressure (volume and temperature of gas remains constant)

They have a directly proportional relationship, because if the amount of gas particles is reduced, the pressure decreases, or if quantity of gas particles increases, the pressure will increase, also.

A simple system to show this would be a bicycle tire:

The tire is rigid, so its volume is essentially constant, and the temperature would remains the same if not moving or driving it.

Using a tire gauge, it is possible to know the manometric pressure inside the tire, that is the difference between the actual pressure inside the tire and the atmospheric pressure.

Then each time that using an air pump some air is injected in the tire, it si possible to check the pressure inside it using the gauge, and observe how is increasing.

Also, is possible to open the valve, to allow some air to escape, then use the gauge to observe how the pressure decreases.

7 0

3 years ago

You are in downtown Chicago (where streets run N-S and E-W). You started from 600 N. Michigan Avenue, and walked 3 blocks toward

pickupchik [31]

Answer:

Displacement is 565.69 m at 45° west of north

Explanation:

Let north represent positive y axis and east represent positive x axis.

We have journey started from 600 N. Michigan Avenue, and walked 3 blocks toward north, 4 blocks toward west, and 1 block toward north to a train station.

3 blocks toward north = 300 j m

4 blocks toward west = -400 i m

1 blocks toward north = 100 j m

Total displacement = -400 i + 400 j m

Magnitude

$s=\sqrt{(-400)^2+400^2}=565.69m$

Direction,

$\theta =tan^{-1}\left ( \frac{400}{-400}\right )=135^0$

Direction is 45° west of north.

Displacement is 565.69 m at 45° west of north

4 0

2 years ago

This is being graded.Great answers only​

This is being graded.Great answers only