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melisa1 [442]
3 years ago
15

Rubbing your hands together warms them by converting work into thermal energy. If a woman rubs her hands back and forth for a to

tal of 18 rubs, at a distance of 7.16 cm per rub, and with an average frictional force of 48 N, what is the temperature increase? The mass of tissues warmed is only 0.1 kg, mostly in the palms and fingers.
Physics
1 answer:
KATRIN_1 [288]3 years ago
6 0

Answer:

0.178 °C

Explanation:

Given:

The frictional force, F = 48 N

Number of rubs, n = 18

Distance covered per rub, d = 7.16 cm = 0.0716 m

Total distance covered in 18 rubs, D = 0.0716 × 18 = 1.288 m

mass of the tissues warmed, m = 0.1 kg

Now,

Work done, W = Force × Displacement

W = 48 × 1.288 = 61.8624 J

Now,

Work done is the change in heat

W = ΔQ = 61.8624 J

also,

ΔQ = mCΔT

where, C is the specific heat

for human tissue, C = 3470 J/kg°C

thus,

61.8624 J = 0.1 × 3470 × ΔT

or

ΔT = 0.178 °C

Hence, the change in temperature is 0.178 °C

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Answer:

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Explanation:

If I normally drive a 12 hour trip at an average speed of 100 km/h, my destination has a total distance of:

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Today, I drive the first 2/3 of the distance at 116 km/h. Let's first calculate what 2/3 of the normal distance is.

  • 1,200 * 2/3 = 800 km

I've driven 800 km already. I need to drive 400 km more to reach my final destination. I need to figure out my average speed during this last 1/3 of the distance.

To do this, I first need to calculate how much time I spent driving 116 km/h for the past 800 km.

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I spent 6.89655172 hours driving during the first 2/3 of the distance.

Now, I need to subtract this value from 12 hours to find the remaining time I have left.

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Using this remaining time and my remaining distance, I can calculate my average speed.

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My average speed during the last third of the distance is around 78 km/h.

8 0
2 years ago
Pls help I really need help w this one Tnks
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6 0
3 years ago
When scientists describe the position of an object accurately, they use a _______________ point.
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I’m pretty sure it’s a starting point... unless it’s asking for an actual object
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To find the relative distance from one point to another it is necessary to apply the Relativity equations.

Under the concept of relativity the distance measured from a spatial object is given by the equation

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Replacing with our values we have that

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Therefore the distance between Mars and Venus measured by the Martin is 7.2*10^{10}m

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