8. A dog runs with an initial speed of 7.5 m/s on a waxed floor. It slides to a stop in 15 sec. What

Two objects are placed in thermal contact and are allowed to come to equilibrium in isolation. The heat capacity of Object A is

kicyunya [3294]

Heat capacity of A is three times that of B

and the initial temperature for A is twice that of B

with TA = 2 TB

Let T denote the final temperature of the system.

The heat lost by A equals the heat gained by B:

mass of A x specific heat of A x (TA - T) = mass of B x specific heat of B x ( T - TB)

which simplifies to heat capacity of A x ( TA - T) = heat capacity of B x ( T - TB)

resulting in 3 x heat capacity of B x ( TA - T) = heat capacity of B x ( T - TB).

This leads us to the equation: 3 TA - 3 T = T - TB

which rearranges to yield 6 TB + TB = 4 T

thus giving us T = 1.75 TB

8 0

1 month ago

A standard 14.16-inch (0.360-meter) computer monitor is 1024 pixels wide and 768 pixels tall. Each pixel is a square approximate

inna [3103]

Answer:

0.0031 m

Explanation:

y = Length of pixel = 281 μm

L = Distance to screen = 1.3 m

$\lambda$ = Wavelength = 550 nm

d = Pupil diameter

$\theta$ = Angle

We have the expression

$tan\theta=\dfrac{y}{L}\\\Rightarrow \theta=tan^{-1}\dfrac{y}{L}\\\Rightarrow \theta=tan^{-1}\dfrac{281\times 10^{-6}}{1.3}$

We have the expression

$sin\theta=1.22\dfrac{\lambda}{d}\\\Rightarrow d=\dfrac{1.22\lambda}{sin\theta}\\\Rightarrow d=\dfrac{1.22\times 550\times 10^{-9}}{sin\left(tan^{-1}\frac{281\times 10^{-6}}{1.3}\right)}\\\Rightarrow d=0.0031\ m$

The pupil diameter calculates to 0.0031 m

4 0

28 days ago

The magnitude of the Poynting vector of a planar electromagnetic wave has an average value of 0.939 W/m2. The wave is incident u

Yuliya22 [3333]

Answer:

The total energy can be expressed as $T = 169.02 \ J$

Explanation:

The problem states that

The Poynting vector, which measures energy flux, equals $k = 0.939 \ W/m^2$

The rectangle's length is represented by $l = 1.5 \ m$

The width of the rectangle is $w = 2.0 \ m$

The duration considered is $t = 1 \ minute = 60 \ s$

Mathematically, the overall electromagnetic energy incident on the area is given by

$T = k * A * t$

where A denotes the area of the rectangle, calculated as

$A= l * w$

By plugging in the respective values

$A= 2 * 1.5$

$A= 3 \ m^2$

Again substituting values

$T = 0.939 * 3 * 60$

$T = 169.02 \ J$

5 0

2 months ago

In pottery class, you throw a pot from a lump of wet clay. your pot's mass is 5.5 kg. after the pot is fired, it's mass is 4.9 k

ValentinkaMS [3465]

To find the volume, we can utilize the ratio of mass to density, as shown by:

volume = mass / density

A. when mass = 5.5 kg = 5500 g; density = 1.60 g/cm^3

volume = 5500 g / (1.60 g/cm^3)

resulting in volume = 3,437.5 cm^3

By rounding according to significant digits:

volume = 3,400 cm^3 = 3.4 L

B. when mass = 4.9 kg = 4900 g; density = 1.36 g/cm^3

volume = 4900 g / (1.36 g/cm^3)

calculating gives volume = 3,602.94 cm^3

Considering significant digits:

<span>volume = 3,600 cm^3 = 3.6 L</span>

8 0

1 month ago

An object initially at rest experiences a constant horizontal acceleration due to the action of a resultant force applied for 10

inna [3103]

Answer:

a = 18.28 ft/s²

Explanation:

the values provided are:

duration of force application, t= 10 s

Work done = 10 Btu

mass of the object = 15 lb

acceleration, a =? ft/s²

1 Btu = 778.15 ft.lbf

thus, 10 Btu = 7781.5 ft.lbf

$m = \dfrac{15}{32.174}\ slug$

m = 0.466 slug

So,

the work is equivalent to the change in kinetic energy

$W = \dfrac{1}{2} m (v_f^2-v_i^2)$

$7781.5 = \dfrac{1}{2}\times 0.466\times v_f^2$

$v_f = 182.75\ ft/s$

The acceleration of the object is therefore

$a = \dfrac{v_f-v_o}{t}$

$a = \dfrac{182.75-0}{10}$

a = 18.28 ft/s²

the constant acceleration of the object is calculated to be 18.28 ft/s²

3 0

2 months ago