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2 years ago

In which of these samples do the molecules most likely have the most kinetic energy? (2 points)

1 answer:

4 0

D, water vapor. Gaseous state would have more kinetic energy, they are moving faster. If you have to compare the same state, then higher temperature would have the higher kinetic energy. But if you have solid and liquid at the same temperature - then liquid would have more.

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A 65 Kg skier starts at rest at the top of a 150 m long hill that has an incline of 28 degrees. How fast will she be going at th

yan [13]

Answer:

34 m/s

Explanation:

Potential energy at top = kinetic energy at bottom + work done by friction

PE = KE + W

mgh = ½ mv² + Fd

mg (d sin θ) = ½ mv² + Fd

Solving for v:

½ mv² = mg (d sin θ) − Fd

mv² = 2mg (d sin θ) − 2Fd

v² = 2g (d sin θ) − 2Fd/m

v = √(2g (d sin θ) − 2Fd/m)

Given g = 9.8 m/s², d = 150 m, θ = 28°, F = 50 N, and m = 65 kg:

v = √(2 (9.8 m/s²) (150 m sin 28°) − 2 (50 N) (150 m) / (65 kg))

v = 33.9 m/s

Rounded to two significant figures, her velocity at the bottom of the hill is 34 m/s.

8 0

3 years ago

As the bright sun shines upon the water, the water slowly disappears. The same sunlight gives energy to the surrounding plans to

mariarad [96]

first is physical .... sec chem

8 0

3 years ago

A plane accelerates from rest at a constant rate of 5.00 m/s2 along a runway that is 1800 m long. Assume that the plane reaches

tiny-mole [99]

Answer:

26.8 seconds

Explanation:

To solve this problem we have to use 2 kinematics equations: *I can't use subscripts for some reason on here so I am going to use these variables:

v = final velocity

z = initial velocity

x = distance

t = time

a = acceleration

${v}^{2} = {z}^{2} + 2ax$

$v = z + at$

First let's find the final velocity the plane will have at the end of the runway using the first equation:

${v}^{2} = {0}^{2} + 2(5)(1800)$

$v = 60 \sqrt{5}$

Now we can plug this into the second equation to find t:

$60 \sqrt{5} = 0 + 5t$

$t = 12 \sqrt{5}$

Then using 3 significant figures we round to 26.8 seconds

3 0

2 years ago

An inventor develops a stationary cycling device by which an individual, while pedaling, can convert all of the energy expended

mr Goodwill [35]

Answer:

$Q=94185\ J$

Explanation:

Given:

mass of water, $m=0.3\ kg$

initial temperature of water, $T_i=20^{\circ}C$

final temperature of water, $T_f=95^{\circ}C$

specific heat of water, $c=4186\ J.kg^{-1}.K^{-1}$

<u>Now the amount of heat energy required:</u>

$Q=m.c.\Delta T$

$Q=0.3\times 4186\times (95-20)$

$Q=94185\ J$

Since all of the mechanical energy is being converted into heat, therefore the same amount of mechanical energy is required.

4 0

3 years ago

Suspend a heavy weight by two pieces of rope. Tension is greatest when the ropes

bija089 [108]

Assuming that the angle is the same for both ropes, then D. is the answer. You have to consider also if the ropes are close together or far apart and if the force to move the object is in line with the ropes or perpendicular to them.
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3 0

3 years ago