How many newtons does a 5-kg backpack weigh on Earth?

Your classmate says that if all the molecules in a particular liquid had the same speed, and some were able to evaporate, the re

babymother [125]

The molecules which evaporate presumably take heat away from the liquid. So, I'd disagree with the classmate. Whether the amount of cooling would differ from the usual case wherein the molecules have different speeds is another question.
I guess the argument goes something along the lines of that the faster moving and therefore most kinetically energetic molecues evaporate and take away most heat. But if there's no faster moving molecules, 'cos they all have the same speed well, then presumably they'd all take away the same amount of heat. So, maybe the cooling would be less. No cooling though ??? Hmmmm dunno .... i think not ....

3 0

3 years ago

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Which of the following characteristics did John Dalton include in his description of the atom?

Luba_88 [7]

Answer:

The answer is "In any element ,all the atoms are the same".

7 0

3 years ago

A Carnot air conditioner takes energy from the thermal energy of a room at 70°F and transfers it as heat to the outdoors, which

IrinaK [193]

Answer:

Explanation:

Given that,

Hot temperature

T_H = 96°F

From Fahrenheit to kelvin

°K = (°F - 32) × 5/9 + 273

°K = (96 - 32) × 5/9 + 273

K = 64 × 5/9 + 273 = 35.56 + 273

K = 308.56 K

T_H = 308.56 K

Low temperature

T_L = 70°F

Same procedure to Levine

T_L = (70-32) × 5/9 + 273

T_L = 294.11 K

A carnot refrigerator working between a hot reservoir and at temperature T_H and a cold reservoir and at temperature T_L has a coefficient of performance K given by

K = T_L / (T_H - T_L)

K = 294.11 / (308.56 - 294.11)

K = 294.11 / 14.45

K = 20.36

Then, the coefficient of performance is the energy Q_L drawn from the cold reservoir as heat divided by work done,

So, for each joules W = 1J

K = Q_L / W

Then,

Q_L = K•W

Q_L = 20.36 × 1

Q_L = 20.36 J

Q_L ≈ 20J

So, approximately 20J of heats are removed from the room

4 0

3 years ago

An object travels for 5 minutes with constant motion. What conclusion can you make about the sum of the forces (total force) act

zheka24 [161]

Using Fnet= ma, constant motion means 0 acceleration, Fnet ( force ) will be also 0

3 0

3 years ago

A worker is using a pulley to lift a 33-kilogram crate. If he applies a force of 129 newtons, the crate is lifted 16.5 meters ab

lapo4ka [179]

Answer:

79.8 %

Explanation:

The energy in input to the system is equal to the work done by the worker, so:

$E_{in} = Fd$

where

F = 129 N is the force applied

d = 16.5 m is the displacement of the rope

Substituting,

$W_{in} = (129)(33)=4257 J$

The output work of the system is the gravitational potential energy gained by the crate, so

$W_{out} = mg \Delta h$

where

m = 33 kg is the mass of the crate

g = 9.8 m/s^2 is the acceleration of gravity

$\Delta h =16.5 m$ is the gain in height of the crate

Substituting,

$W_{out}= (33)(9.8)(16.5)=5336 J$

So, the efficiency of the pulley is

$\eta = \frac{W_{in}}{W_{out}}=\frac{4257}{5336}=0.798$

So, 79.8 %.

6 0

3 years ago