All categories

3 years ago

Which of the following is the best explanation for acceleration? *

Physics

1 answer:

Anuta_ua [19.1K]3 years ago

8 0

Answer:the rate of change in velocity

Explanation: acceleration =the change in velocity / time taken the unit is m/s2

While velocity is the distance traveled in a given direction/time taken.the unit is m/s

You might be interested in

When you go out into the sun, the UV light can give you a tan. UV light has a frequency of 7.89 x 1014 Hz. What is the wavelengt

Olin [163]

Answer:

Explanation:

Formula and givens

λ = c / f
λ is the wavelength
c = the speed of light
f = the frequency
c = 3*10^8
f = 7.89 * 10^14

λ = ?

Solution

λ = 3*10^8 / 7.89*10^14

λ = 3*10^8/7.89*10^14

λ = 2.36 * 10^7

λ = 236 nanometers. What you use as your solution depends on what what you have been taught.

6 0

3 years ago

Describe how a wheel and axle work?

andrezito [222]

A weally works when you pull something and a axle is something that you can push

Explanation:

I hope this helps

7 0

2 years ago

A 12 cm diameter piston-cylinder device contains air at a pressure of 100 kPa at 24oC. The piston is initially 20 cm from the ba

lina2011 [118]

Answer:

ΔQ = 0.1 kJ

$\mathbf{v_f = 1.445*10^{-3} m^3}$

$\mathbf{P_f = 156.5 \ kPa}$

ΔS = -0.337 J/K

The value negative is due to the fact that there is need to be the same amount of positive change in surrounding as a result of compression.

Explanation:

GIven that:

Diameter of the piston-cylinder = 12 cm

Pressure of the piston-cylinder = 100 kPa

Temperature =24 °C

Length of the piston = 20 cm

Boundary work ΔW = 0.1 kJ

The gas is compressed and The temperature of the gas remains constant during this process.

We are to find ;

a. How much heat was transferred to/from the gas?

According to the first law of thermodynamics ;

ΔQ = ΔU + ΔW

Given that the temperature of the gas remains constant during this process; the isothermal process at this condition ΔU = 0.

Now

ΔQ = ΔU + ΔW

ΔQ = 0 + 0.1 kJ

ΔQ = 0.1 kJ

Thus; the amount of heat that was transferred to/from the gas is : 0.1 kJ

b. What is the final volume and pressure in the cylinder?

In an isothermal process;

Workdone W = $\int dW$

$W = \int pdV \\ \\ \\W = \int \dfrac{nRT}{V}dv \\ \\ \\ W = nRt \int \dfrac{dv}{V} \\ \\ \\ W = nRT In V |^{V_f} __{V_i}} \\ \\ \\ W = nRT \ In \dfrac{V_f}{V_i}$

Since the gas is compressed ; then $v_f< v_i$

However;

$W =- nRT \ In \dfrac{V_f}{V_i}$

$W =- P_1V_1 \ In \dfrac{V_f}{V_i}$

The initial volume for the cylinder is calculated as ;

$v_1 = \pi r^2 h \\ \\ v_1 = \pi r^2 L \\ \\ v_1 = 3.14*(6*10^{-2})^2*(20*10^{-2}) \\ \\ v_1 = 2.261*10^{-3} \ m^3$

Replacing over values into the above equation; we have :

$100 = - ( 100*10^3 *2.261*10^{_3}) In (\dfrac{v_f}{v_i}) \\ \\ - In (\dfrac{v_f}{v_i})= \dfrac{100}{(100*10^3*2.261*10^{-3})} \\ \\ - In \ v_f + In \ v_i = \dfrac{100}{226.1} \\ \\ - In \ v_f = - In \ v_i + \dfrac{100}{226.1} \\ \\ - In \ v_f = - In (2.261*10^{-3} + \dfrac{100}{226.1 } \\ \\ - In \ v_f = 6.1 + 0.44 \\ \\ - In \ v_f = 6.54 \\ \\ - In \ v_f = -6.54 \\ \\ v_f = e^{-6.54} \\ \\ \mathbf{v_f = 1.445*10^{-3} m^3}$

The final pressure can be calculated by using :

$P_1V_1 = P_2V_2 \\ \\ P_iV_i = P_fV_f$

$P_f =\dfrac{P_iV_i}{V_f}$

$P_f =\dfrac{100*2.261*10^{-3}}{1.445*10^{-3}}$

$P_f = 1.565*10^2 \ kPa$

$\mathbf{P_f = 156.5 \ kPa}$

c. Find the change in entropy of the gas. Why is this value negative if entropy always increases in actual processes?

The change in entropy of the gas is given by the formula:

$\Delta S=\dfrac{\Delta Q}{T}$

where

T = 24 °C = (24+273)K

T = 297 K

$\Delta S=\dfrac{-100 \ J}{297 \ K}$

ΔS = -0.337 J/K

The value negative is due to the fact that there is need to be the same amount of positive change in surrounding as a result of compression.

4 0

2 years ago

What types of simple machine is wheel and<br>axle?<br>

astra-53 [7]

Answer:

lever is the correct answer to the given question .

Explanation:

The main purpose of wheel and axle to Migrating the particles as well as elevate the objects and the people.The wheel is the rounded disk or it may be the the rectangular outer part and the axle is the curved cylinder.

The axle is operating via the center square So they are connected to the various object.
The wheel and the axle applications involve trying to lifting the large loads as well as pushing the things rapidly.

6 0

2 years ago

Which describe the image formed by an object on the center of curvature? Check all that apply.

9966 [12]

The image formed by a concave mirror with the object placed at the center of curvature is real inverted and formed at the center of curvature. Using the ray diagram a ray from the top of the object to the mirror through f then reflected parallel to the principal axis,then the ray through the center of curvature reflected through the same point both intersect at a plane through center curvature and perpendicular to the principal axis. The point of intersection forms the top of the image and the center of curvature forms the bottom. Therefore, the correct choices are : real and inverted

5 0

3 years ago

Read 2 more answers