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2 years ago

9

What is the speed of an object at rest? a. 0.0 m/s c. 9.8 m/s b. 1.0 m/s d. 9.81 m/s

1 answer:

pishuonlain [190]2 years ago

8 0

Answer:

A 0.0 m/s

An object at rear is not moving so it is morning 0m every second.

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A common method to measure thermal conductivity of a biomaterial is to insert a long metallic probe axially into the center of a

tia_tia [17]

Answer:

The thermal conductivity of the biomaterial is approximately 1.571 watts per meter-Celsius.

Explanation:

Let suppose that thermal conduction is uniform and one-dimensional, the conduction heat transfer ( $\dot Q$ ), measured in watts, in the hollow cylinder is:

$\dot Q = \frac{2\cdot k\cdot L}{\ln \left(\frac{D_{o}}{D_{i}} \right)}\cdot (T_{i}-T_{o})$

Where:

$k$ - Thermal conductivity, measured in watts per meter-Celsius.

$L$ - Length of the cylinder, measured in meters.

$D_{i}$ - Inner diameter, measured in meters.

$D_{o}$ - Outer diameter, measured in meters.

$T_{i}$ - Temperature at inner surface, measured in Celsius.

$T_{o}$ - Temperature at outer surface, measured in Celsius.

Now we clear the thermal conductivity in the equation:

$k = \frac{\dot Q}{2\cdot L\cdot (T_{i}-T_{o})}\cdot \ln\left(\frac{D_{o}}{D_{i}} \right)$

If we know that $\dot Q = 40.8\,W$ , $L = 0.6\,m$ , $T_{i} = 50\,^{\circ}C$ , $T_{o} = 20\,^{\circ}C$ , $D_{i} = 0.01\,m$ and $D_{o} = 0.04\,m$ , the thermal conductivity of the biomaterial is:

$k = \left[\frac{40.8\,W}{2\cdot (0.6\,m)\cdot (50\,^{\circ}C-20\,^{\circ}C)}\right]\cdot \ln \left(\frac{0.04\,m}{0.01\,m} \right)$

$k \approx 1.571\,\frac{W}{m\cdot ^{\circ}C}$

The thermal conductivity of the biomaterial is approximately 1.571 watts per meter-Celsius.

8 0

3 years ago

A particle is moving along the x-axis. Its position as a function of time is given as x=bt-ct^2a) What must be the units of the

lisabon 2012 [21]

Answer:

We are given x= bt +ct²

So

A. bxt= m

Because m/s*s= m

So b= m/s and c= m/s²

B.

x= bt-ct²

So at x=0 t=0

x=0 t= 2

We have

bt = ct² so t = b/c at x= 0

So b-2ct= 0

B. To find velocity we use

dx / dt = b - 2 Ct

C. At rest wen V= 0

We have t= b/2c

D. To find acceleration we use

dv / dt = - 2C

3 0

3 years ago

Three common elements that can reorient their electrons into magnetic domains and become magnetic are iron, nickel, and ________

ohaa [14]

Answer:

Cobalt

Explanation:

8 0

3 years ago

Why does a metal spoon left on a bowl of hot soup become warm? A) Metal is a conductor. B) Metal is an insulator. C) Metal produ

mr_godi [17]

A: Metal is a conductor it hold the heat

5 0

3 years ago

Read 2 more answers

what was the initial temperature is 250 calories reply .1 kg of gold the final temperature of the gold was 175°c ? the specific

weqwewe [10]

Answer:

$115.2^{\circ}C$

Explanation:

When an amount of energy Q is supplied to a substance of mass m, the temperature of the substance increases by $\Delta T$ , according to the equation

$Q=mC_s \Delta T$

where $C_s$ is the specific heat capacity of the substance.

In this problem, we have:

$Q=250 \cdot 4.184 =1046 J$ is the amount of heat supplied to the sample of gold

m = 0.1 kg = 100 g is the mass of the sample

$C_s = 0.175 J/gC$ is the specific heat capacity of gold

Solving for $\Delta T$ , we find the change in temperature

$\Delta T = \frac{Q}{m C_s}=\frac{1046}{(100)(0.175)}=59.8^{\circ}$

And since the final temperature was

$T_f = 175^{\circ}$

The initial temperature was

$T_i = T_f - \Delta T= 175 -59.8=115.2^{\circ}C$

3 0

3 years ago