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3 years ago

A silver bar with a mass of 250.0 g is heated from 22.0°C to 68.5°C. How much heat does the silver bar absorb?

Physics

1 answer:

Harrizon [31]3 years ago

8 0

Answer:

Q = 2790 J

Explanation:

Mass of silver bar is 250 g

It is heated from 22.0°C to 68.5°C

The specific heat of silver is 0.240 J/g°C

It is required to find the heat absorb by the silver bar. The heat absorbed by an object when heated from one temperature to another is given by :

$Q=mc\Delta T\\\\Q=250\times 0.240\times (68.5-22)\\\\Q=2790\ J$

So, the heat absorbed by the silver bar is 2790 J.

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A small fish is dropped by a pelican that is rising steadily at 0.50 m/s.

natima [27]

Answer:

(a) 24.025 m/s. downward.

(b) 31 m

Explanation:

From Newton's equation of motion,

(a)

v = u + gt ................... Equation 1

Where v = final velocity, u = initial velocity, g = acceleration due to gravity, t = time.

Note: Let upward velocity be negative and downward be positive

Given: u = -0.5 m/s (upward), t = 2.5 s

Constant : g = 9.81 m/s²

Substitute into equation 1

v = 0.5+9.81(2.5)

v = -0.5+24.525

v = 24.025 m/s. downward.

(b) using

s₁ = ut + 1/2gt²......................... Equation 2

Where s₁ = distance at which the fish fall after being dropped by the pelican

Given: u = - 0.5 m/s, t = 2.5 s, g = 9.81 m/s²

Substitute into equation 2

s₁ = -0.5(2.5) + 1/2(9.81)(2.5)²

s₁ = -1.25+30.656

s₁ = 29.41 m

also,

s₂ = vt ................ Equation 3

Where s₂ = the distance by which the pelican rise during this time.

Given: v = 0.5 m/s, t= 2.5 s

s₂ = 0.5(2.5)

s₂ = 1.25 m.

Note: Distance between the pelican and fish = s₁ + s₂

Distance between the pelican and fish = 29.41+1.25

Distance between the pelican and fish = 30.66

Distance between the pelican and fish ≈ 31 m

3 0

3 years ago

1. At the synaptic terminal, voltage-gated ______________ channels open, thereby stimulating the synaptic vesicles to release th

Sergeeva-Olga [200]

Ion

<u>Explanation:</u>

At the synaptic terminal, voltage-gated ion channels open, thereby stimulating the synaptic vesicles to release the neurotransmitters by exocytosis.

These ion channels are the signaling molecules in neurons. They are the transmembrane proteins that form ion channels. The membrane potential changes the conformation of the channel proteins that regulates their opening and closing. These channels play an important role in neurotransmitter release in presynaptic nerve endings.

For example - Ca²⁺ gated ion channel.

4 0

3 years ago

Which factor (s) have the most affect a person’s vital capacity? Rank in order from MOST effect (1) to least effect (5)

jenyasd209 [6]

The factors that affect vital capacity are :

Age
Sex
Height
Body mass
Ethnicity

Explanation:

Vital capacity is the maximum amount of air that a person can exhale once he has filled his lungs with maximum air. So, it is like maximum exhalation after maximum inhalation by a person.

Vital capacity is also equal to Forced Vital Capacity.

Lung usually have their maximum capacity in early adult days and this capacity reduces as the person grows older. So age is the prime factor in this.

A female with same age and height as that of male will have 10-12% less vital capacity than him. So sex is another reason which determines vital capacity.

Person with more height has more vital capacity. This is because lungs capacity is closely related to the third power of person's height.

Person suffering from obesity will have compressed diaphragm, lung and chest cavity , so their vital capacity will be less. So we can say body mass affects vital capacity.

Last factor, ethnicity, is yet to be understood clearly as there is not much evidence of this.

3 0

3 years ago

Networks of interconnected wireless devices that are embedded into the physical environment to provide measurements of many poin

bazaltina [42]

Wireless sensor networks

Explanation:

Networks of interconnected wireless devices that are embedded into the physical environment to provide measurements of many points over a large spaces are called Wireless sensor networks.

They are very useful in obtaining real-time data and information about every day life.

The internet of things greatly relies on the use of wireless sensor networks in devices and gadgets to better and improve life.
They are constantly in use by various organizations and bodies.
Wireless sensor networks can be designed to collect specific scientific data or even more.

learn more:

Connecting IoT devices brainly.com/question/11028028

#learnwithBrainly

6 0

4 years ago

10. A spring whose composition is not completely known might be either bronze (sp gr 8.8) or brass (sp gr 8.4). It has a mass of

frez [133]

The element used is of bronze.

Now before we find out how we got the answer as bronze, firstly let us understand about the device we are talking about. That is, spring.

What exactly is a spring?

A spring is defined as a device that changes its shape in response to an external force, returning to its original shape when the force is removed. If we apply force or pressure in this device, it will change its shape but the moment we stop applying force, it will come back to its original state.

This means that this device is made of something flexible. So, the material it is made up of should also be flexible in nature.

How to find out flexibility of spring?

Flexibility of spring can be found as q = f Q, where f is the spring flexibility.

Here, in this question, we are given the mass of element in air and water. This shows a slight comparison between the mass of that particular element in air and water and thus, we get to know it is trying to draw our attention towards density.

Here, we have mass in air and water, thus, we can determine the density.

From these numbers, we can know that the density given is of bronze.

Hence, the element used is Bronze.

To know more spring aggregate, refer : brainly.com/question/20215636

#SPJ4

7 0

1 year ago