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3 years ago

Which types of heat transfer involve heat flow from hot objects to colder objects?

Physics

2 answers:

Alex3 years ago

8 0

Answer:

convection, conduction, and radiation

Explanation: Study Island

konstantin123 [22]3 years ago

4 0

Thermal radiation is a form of heat transfer because the electromagnetic radiation emitted from the source carries energy away from the source to surrounding objects

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Multiple Intelligences :

vlada-n [284]

Answer:

all of the above

PLS MARK ME AS BRAINLIAST

8 0

3 years ago

What would the acceleration of a car be from a stoplight if it started at 0 m/s and reached a

trapecia [35]

Answer:

The acceleration of a car would be: $a=12.8$ m/s²

Explanation:

Given

Initial velocity = $v_1=0$ m/s

Final velocity = $v_f=100$ m/s

Time elapsed = $t = 7.8$ s

To determine

We need to determine the acceleration of a car.

We know that acceleration is basically the rate of change in velocity over time.

Thus,

We can determine the acceleration using the formula

$\:\:\:a=\:\frac{v_f-v_i}{t}$

where

$a$ is the acceleration

$v_1$ is the initial velocity

$v_f$ is the final velocity

$t$ is time elapsed

now substituting the values $v_1=0$ , $v_f=100$ , and $t = 7.8$ in the formula

$\:\:\:a=\:\frac{v_f-v_i}{t}$

$a=\:\frac{100-0}{7.8}$

$a=\frac{100}{7.8}$

$a=12.8$ m/s²

Therefore, the acceleration of a car would be: $a=12.8$ m/s²

3 0

3 years ago

A single roller-coaster car is moving with speed v0 on the first section of track when it descends a 4.7-m-deep valley, then cli

yan [13]

Explanation:

From the curve given in the attachment,

a) minimum speed v0 required if the car is to travel beyond the top of the hill

climb to the top = 5.4 m

Therefore, $V_0=\sqrt{2gh}$

$V_0=\sqrt{2(9.81)(5.4)}$ = 10.29 m/s

b) No, we cannot affect this speed by changing the depth of the valley to make the coaster pick up more speed at the bottom as this speed does not depend upon depth of the valley.

5 0

3 years ago

A hot-water stream at 80 ℃ enters a mixing chamber with a mass flow rate of 0.5 kg/s where it is mixed with a stream of cold wat

rewona [7]

Answer:

$\dot{m_{2}}=0.865 kg/s$

Explanation:

$\dot{m_1}= 0.5kg/s$

from steam tables , at 250 kPa, and at

T₁ = 80⁰C ⇒ h₁ = 335.02 kJ/kg

T₂ = 20⁰C⇒ h₂ = 83.915 kJ/kg

T₃ = 42⁰C ⇒ h₃ = 175.90 kJ/kg

we know

$\dot{m_{in}}=\dot{m_{out}}$

$\dot{m_{1}}+\dot{m_{2}}=\dot{m_{3}}$

according to energy balance equation

$\dot{m_{in}}h_{in}=\dot{m_{out}}h_{out}$

$\dot{m_{1}}h_{1}+\dot{m_{2}}h_{2}=\dot{m_{3}}h_{3}$

$\dot{m_{1}}h_{1}+\dot{m_{2}}h_{2}=(\dot{m_{1}}+\dot{m_{2}})h_{3}\\(0.5\times 335.02)+(\dot{m_{2}}\times 83.915)=(0.5+\dot{m_{2}})175.90\\\dot{m_{2}}=0.865 kg/s$

4 0

4 years ago

1. what factor does work depends on? 2. what factor does power depends on?

Harrizon [31]

1.motivation 2. ????

5 0

3 years ago