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2 years ago

Hi all, can u please help me in this. I would very appreciate it :)

Physics

1 answer:

andreyandreev [35.5K]2 years ago

7 0

Questions And Answers About Air Resistance.

Question 1: What is Air resistance?

Answer: Air resistance is a force that is caused by air. The force acts in the opposite direction to an object moving through the air. A lorry with a flat front will experience high air resistance while a sports car with a streamlined shape will experience lower air resistance, allowing the car to go faster.

Question 2: What causes air resistance?

Answer: Air resistance, also known as drag, is a force that is caused by air, the force acts in the opposite direction to an object moving through the air. It is where air particles hit the front of the object slowing it down. The more surface area, the more air particles hit it and the greater the resistance.

Question 3: How can air resistance be overcome?

Answer: Two ways to reduce air resistance are stated: reducing the area in contact with air (by the cyclist ducking down or cycling behind someone else) and by being more streamlined (wearing smoother surfaces or a more streamlined helmet).

Question 4: What happens when air resistance increases?

Answer: As it gains speed, the object's weight stays the same but the air resistance on it increases. There is a resultant force acting downwards. Eventually, the object's weight is balanced by the air resistance. There is no resultant force and the object reaches a steady speed – this is known as the terminal velocity.

Questions And Answers About Water Resistance.

Question 1: What is Water resistance?

Answer: Water resistance is a type of force that uses friction to slow things down that are moving through water. ... Water resistance occurs because of the particles in the liquid. As an object moves through a liquid, it collides with the particles which cause it to slow down.

Question 2: What causes water resistance?

Answer: Water resistance doesn't have to be just water, however, it can happen to objects moving through any type of fluid. Water-resistance happens because of the particles in water or the fluid. As the object moved through it collides with the particles which try to slow it down.

Question 3: How is water resistance useful?

Answer: Like friction and air resistance, it SLOWS THINGS DOWN, trying to stop them from moving. Water resistance can also be useful at times. When you are swimming and you push against the water with your hands, the water-resistance pushes back and helps you to move forward. This also happens when you use oars to row a boat.

Question 4: Does water-resistant mean waterproof?

Answer: The technical definition of water-resistant is that it's able to resist the penetration of water to a certain degree, but not entirely. Waterproof technically means that it's impermeable to water, no matter how much time it spends in the water.

Hope This Helps...:)

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A physicist is investigating a beam of laser light of wavelength 550 nm. The light strikes a target that is 189 meters away from

Lena [83]

Answer: here you go I was looking for this answer everywhere,I have it now so it’s 6.30 x 10^-7 s

Explanation:

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3 years ago

The rate at which heat enters an air conditioned building is often roughly proportional to the difference in temperature between

erma4kov [3.2K]

Answer:

Considering first question

Generally the coefficient of performance of the air condition is mathematically represented as

$COP = \frac{T_i}{T_o - T_i}$

Here $T_i$ is the inside temperature

while $T_o$ is the outside temperature

What this coefficient of performance represent is the amount of heat the air condition can remove with 1 unit of electricity

So it implies that the air condition removes $\frac{T_i}{T_o - T_i}$ heat with 1 unit of electricity

Now from the question we are told that the rate at which heat enters an air conditioned building is often roughly proportional to the difference in temperature between inside and outside. This can be mathematically represented as

$Q \ \alpha \ (T_o - T_i)$

=> $Q= k (T_o - T_i)$

Here k is the constant of proportionality

since 1 unit of electricity removes $\frac{T_i}{T_o - T_i}$ amount of heat

E unit of electricity will remove $Q= k (T_o - T_i)$

$E = \frac{k(T_o - T_i)}{\frac{T_i}{ T_h - T_i} }$

=> $E = \frac{k}{T_i} (T_o - T_i)^2$

given that $\frac{k}{T_i}$ is constant

=> $E \ \alpha \ (T_o - T_i)^2$

From this above equation we see that the electricity required(cost of powering and operating the air conditioner) is approximately proportional to the square of the temperature difference.

Considering the second question

Assuming that $T_i = 30 ^oC$

and $T_o = 40 ^oC$

Hence

$E = K (T_o - T_i)^2$

Here K stand for a constant

$E = K (40 - 30)^2$

=> $E = 100K$

Now if the $T_i = 20 ^oC$

Then

$E = K (40 - 20)^2$

=> $E = 400 \ K$

So from this see that the electricity require (cost of powering and operating the air conditioner)when the inside temperature is low is much higher than the electricity required when the inside temperature is higher

Considering the third question

Now in the case where the heat that enters the building is at a rate proportional to the square-root of the temperature difference between inside and outside

We have that

$Q = k (T_o - T_i )^{\frac{1}{2} }$

$E = \frac{k (T_o - T_i )^{\frac{1}{2} }}{\frac{T_i}{T_o - T_i} }$

=> $E = \frac{k}{T_i} * (T_o - T_i) ^{\frac{3}{2} }$

Assuming $\frac{k}{T_i}$ is a constant

Then

$E \ \alpha \ (T_o - T_i)^{\frac{3}{2} }$

From this above equation we see that the electricity required(cost of powering and operating the air conditioner) is approximately proportional to the square root of the cube of the temperature difference.

4 0

2 years ago

PLS ANSWER FAST TIMED TEST WILL GIVE BRAINLY!!!!!!!!!

lutik1710 [3]

The answer would be true

7 0

3 years ago

Read 2 more answers

If 128 v is required to push 4.00 A of current though a resistor, what is the resistance

prisoha [69]

Answer:

32.0 Ω

Explanation:

Ohm's law:

V = IR

128 V = (4.00 A) R

R = 32.0 Ω

8 0

2 years ago

Density: Two blocks, A and B, are put in a tank of water. Block A has a density of 1.21 g/cm³. Block B has a density of 1.37 g/c

stira [4]

Answer:

Block A

Explanation:

Block A will float higher in the water compared to the second Block.

The density of water is 1g/cm³.

According to the principle of floatation "an object that floats in a liquid will displace equal amount of fluid to the weight of the object".

A body will become more submerged in water if it has more density because density is the mass per volume of body.

An object with a higher density than another will sink in the liquid of the one with lesser density.

Object A has lesser density and will float higher up and displace very little water.
Object B has higher density and will be more submerged.

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2 years ago