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3 years ago

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Two objects made of the same material are heated to 60 oC and 90 oC. According to

2 answers:

earnstyle [38]3 years ago

6 0

Answer:

The newton law of cooling is:

dQ/dt = -h*a(To - Ta)

Where h and a are constants, To is the temperature of the object and Ta is the temperature of the ambient.

this means that initially if in both cases Ta is the same, the object with higher temperature cools faster.

Now, obviously, if we want to know which object cools faster to a given temperature, for example, 30°C, the object with 60°C will reach that temperature in less time than the other one. (this is because the hot object cools faster at the beginning, but as it starts to lose temperature, the rate at which it colls starts to decrease)

nlexa [21]3 years ago

4 0

Assuming that there is in a vacuum, the two object will cool at the same rate, because the objects are made of the same material they will have the same cooling rate, assuming the surrounding temperature is the same.

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The ideal mechanical advantage of an inclined plane is 3.5, and its efficiency is 0.6. What is the mechanical advantage of the i

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Mechanical advantage = ideal mechanical advantage x efficiency = 3.5 x 0.6 = 2.1
The mechanical advantage of the inclined plane is 2.1

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3 years ago

Which equation can be used to solve for acceleration? <br><br>

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A = d/t
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3 years ago

Read 2 more answers

Two light bulbs have resistances of 400 Ω and 800 ΩThe two light bulbs are connected in series across a 120- V line. Find the cu

Natasha2012 [34]

1) Current in each bulb: 0.1 A

The two light bulbs are connected in series, this means that their equivalent resistance is just the sum of the two resistances:

$R_{eq}=R_1 + R_2 = 400 \Omega + 800 \Omega=1200 \Omega$

And so, the current through the circuit is (using Ohm's law):

$I=\frac{V}{R_{eq}}=\frac{120 V}{1200 \Omega}=0.1 A$

And since the two bulbs are connected in series, the current through each bulb is the same.

2) 4 W and 8 W

The power dissipated by each bulb is given by the formula:

$P=I^2 R$

where I is the current and R is the resistance.

For the first bulb:

$P_1 = (0.1 A)^2 (400 \Omega)=4 W$

For the second bulb:

$P_1 = (0.1 A)^2 (800 \Omega)=8 W$

3) 12 W

The total power dissipated in both bulbs is simply the sum of the power dissipated by each bulb, so:

$P_{tot} = P_1 + P_2 = 4 W + 8 W=12 W$

3 0

3 years ago

A motorist travels at 270 km in p hours at a certain average speed. an expression for the distance that this motorist travelled

wel

Average speed = total distance / time ⇒ total distance = average speed * time

Average speed = 270 km / p hours
distance = d
hours = x

d = 270/p * x

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3 years ago

John’s mass is 95.6 kg, and Barbara’s is 55.3 kg. He is standing on the x axis at xJ = +10.9 m, while she is standing on the x a

Anna11 [10]

Answer:Shifted towards Left by distance of 2.243 m

Explanation:

Given

Mass of john $m_1=95.6 kg$

Mass of barbara $m_2=55.3 kg$

John is standing at $x=10.9 m$

Barbara is standing at $x=2.50 m$

$x_{com}=\frac{m_1x_1+m_2x_2}{m_1+m_2}$

$x_{com}=\frac{95.6\times 10.9+55.3\times 2.5}{95.6+55.3}$

$x_{com}=\frac{1180.29}{150.9}$

$x_{com}=7.821 m$

Now if they change their Position then

$x'_{com}=\frac{95.6\times 2.5+55.3\times 10.9}{95.6+55.3}$

$x'_{com}=\frac{841.77}{150.9}$

$x'_{com}=5.578$

Thus we can see that center of mass shifted towards left by a distance of $2.243 m$ because heavier is shifted towards left

8 0

3 years ago