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raketka [301]
3 years ago
12

Which of the following involves an endothermic reaction?

Physics
2 answers:
pav-90 [236]3 years ago
8 0
The answer would be c
photoshop1234 [79]3 years ago
7 0
It’s c :) A chemical hand warmer
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A 560-g squirrel with a surface area of 930cm2 falls from a 5.0-m tree to the ground. Estimate its terminal velocity. (Use a dra
bija089 [108]

Explanation:

Terminal velocity is given by:

v_t=\sqrt{\frac{2mg}{\rho C_dA}}

Here, m is the mass of the falling object, g is the gravitational acceleration,  C_d is the drag coefficient, \rho is the fluid density through which the object is falling, and A is the projected area of the object. in this case the projected area is given by:

A=\frac{A_s}{2}=\frac{930cm^2}{2}=465cm^2\\465cm^2*\frac{1m^2}{10^4cm^2}=0.0465m^2\\560g*\frac{1kg}{10^3g}=0.56kg

Recall that drag coefficient for a horizontal skydiver is equal to 1 and air density is 1.28\frac{kg}{m^3}.

v_t=\sqrt{\frac{2(0.56kg)(9.8\frac{m}{s^2})}{(1.28\frac{kg}{m^3}(1)(0.0465m^2)}}\\v_t=13.58\frac{m}{s}

Without drag contribution the motion of the person is an uniformly accelerated motion, thus:

v_f^2=v_o^2+2gh\\v_f=\sqrt{2gh}\\v_f=\sqrt{2(9.8\frac{m}{s^2})(5m)}\\v_f=9.9\frac{m}{s}

7 0
3 years ago
Which of these is a unit of heat? <br> a. joule <br> b. degree celsius <br> c. kelvin <br> d. tesla
attashe74 [19]

-- Heat is a form of energy.
-- Joule is the SI unit of energy.
ergo
-- Joule is a unit of heat.

'Degree Celsius' and 'Kelvin' are units of temperature.
Heat and temperature are different things.
We won't go there right now.
3 0
3 years ago
What is the charge of the negative sphere
tatyana61 [14]

Answer:

electrons

Explanation:

8 0
3 years ago
If your car is moving at 100 km/hr, how many kilometers will your car travel in 15 minutes?
steposvetlana [31]
It will be 25 if the car moves at that speed for 15 minutes
8 0
1 year ago
Smaller mammals use proportionately more energy than larger mammals; that is, it takes more energy per gram to power a mouse tha
timama [110]

Answer:

10,200 Cal. per day

Explanation:

The mouse consumes 3.0 Cal each day, and has a mass of 20 grams. We can use this data to obtain a ratio of energy consumption per mass

\frac{3.0 \ Cal}{20 g} = 0.15 \frac{Cal}{g}.

For the human, we need to convert the 68 kilograms to grams. We can do this with a conversion factor. We know that:

1 \ kg = 1000 \ g,

Now, we can divide by 1 kg on each side

\frac{1 \ kg}{1 \ kg} = \frac{1000 \ g}{1 \ kg},

1 = \frac{1000 \ g}{1 \ kg}.

Using this conversion factor, we can obtain the mass of the human in grams, instead of kilograms. First, lets take:

mass_{human} = 68 \ kg

We can multiply this mass for the conversion factor, we are allowed to do this, cause the conversion factor equals 1, and its adimensional

mass_{human} = 68 \ kg * \frac{1000 \ g}{1 \ kg}

mass_{human} = 68,000 g

Now that we know the mass of the human on grams, we can multiply for our ratio of energy consumption

68,000 \ g * 0.15 \frac{Cal}{g} = 10,200 \ Cal

So, we would need 10,200  Cal per day.

3 0
3 years ago
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