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4 years ago

How is heat energy transferred from a warm object to a cold object there is direct contact?

Physics

2 answers:

sdas [7]4 years ago

8 0

A is the answer!!!!!!!!!!!!

eduard4 years ago

4 0

Answer: The heat is getting transferred by conduction.

Explanation:

There are 3 modes of heat transfer:

Conduction: This type of heat transfer happens when there is direct contact between the two objects.
Convection: This type of heat transfer happens when there is a movement of fluid (liquid or gas).
Radiation: This type of heat transfer happens when there is direct transfer of energy through space.

We are given:

Heat energy is getting transferred from a warm object to cold object by direct contact.

Hence, the heat is getting transferred by conduction.

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A hockey puck slides off the edge of a horizontal platform with an initial velocity of 28.0 m/shorizontally in a city where the

kozerog [31]

Answer:

θ = 12.60°

Explanation:

In order to calculate the angle below the horizontal for the velocity of the hockey puck, you need to calculate both x and y component of the velocity of the puck, and also you need to use the following formula:

$\theta=tan^{-1}(\frac{v_y}{v_x})$ (1)

θ: angle below he horizontal

vy: y component of the velocity just after the puck hits the ground

vx: x component of the velocity

The x component of the velocity is constant in the complete trajectory and is calculated by using the following formula:

$v_x=v_o$

vo: initial velocity = 28.0 m/s

The y component is calculated with the following equation:

$v_y^2=v_{oy}^2+2gy$ (2)

voy: vertical component of the initial velocity = 0m/s

g: gravitational acceleration = 9.8 m/s^2

y: height

You solve the equation (2) for vy and replace the values of the parameters:

$v_y=\sqrt{2gy}=\sqrt{2(9.8m/s^2)(2.00m)}=6.26\frac{m}{s}$

Finally, you use the equation (1) to find the angle:

$\theta=tan^{-1}(\frac{6.26m/s}{28.0m/s})=12.60\°$

The angle below the horizontal is 12.60°

7 0

3 years ago

A pulley system has an efficiency of 74.2%. If you perform 200 J of work, how much useful work does the pulley perform?

kirill115 [55]

Efficiency is the measure of how efficient a process is. It is used to assess the ability of a process in avoiding waste energy, materials, money and time in doing a desirable output. It is calculated as;

Efficiency = useful energy ouput / total energy input

.742 = useful energy / 200 J
Useful energy = 148.4 J <-----------OPTION B

7 0

3 years ago

fossil fuels are formed by the decomposition of dead plants and animals. which flow chart describes the correct energy transform

umka2103 [35]

Chemical to kinetic +( heat + sound)

The energy formations in brackets are wasted and passed on to their surroundings.

Hope this helps! :)

8 0

3 years ago

What is the difference between a line that has a slope versus a line that is flat in a position vs. time graph?

MaRussiya [10]

Answer:

a slope means that object is accelerating

and a line means its moving at a constant speed

Explanation:

8 0

3 years ago

A magnet is pushed into a solenoid of 20 coils with a cross-sectional area of 4.0x10-4 m2. As a result, the magnetic field insid

kobusy [5.1K]

Given:

The number of the coils, N=20

The cross-sectional area of the solenoid, A=4.0×10⁻⁴ m²

The magnetic fields, B₁=0.0500 T

and B₂=0.180 T

The time interval, t=1.90 s

The resistance of the resistor, R=1.90 s

To find:

1. The magnitude of the induced emf.

2. The current flowing through the resistor.

Explanation:

The magnitude of the induced emf in the solenoid is given by,

$E=NA\frac{(B_2-B_1)}{t}$

On substituting the known values,

$\begin{gathered} E=20\times4.0\times10^{-4}\times\frac{(0.180-0.0500)}{1.90} \\ =0.55\times10^{-3}\text{ V} \\ =0.55\text{ mV} \end{gathered}$

From Ohm's law, The induced emf is given by,

$E=IR$

On substituting the known values,

$\begin{gathered} 0.55\times10^{-3}=I\times5 \\ \Rightarrow I=\frac{0.55\times10^{-3}}{5} \\ =0.11\times10^{-3}\text{ A} \\ =0.11\text{ mA} \end{gathered}$

Final answer:

1. The induced emf is 0.55 mV

2. The current through the given resistor is 0.11 mA

4 0

2 years ago