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3 years ago

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15. Find the speed of a disc of radius 0.5 meters and mass 2-kg at the base of the incline. The disc starts at rest and rolls do

wn the incline with a height of 5 meters without slipping. The incline makes a 20° angle with the horizontal surface.

1 answer:

mote1985 [20]3 years ago

7 0

Explanation:

sorry_______________

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(a) An object that has a small mass and an object that has a large mass have the same momentum. Which object has the largest kin

Iteru [2.4K]

Answer:

A) The smaller object; B) The larger object

Explanation:

A) Lets say the small object is 2 kg and the large one is 6 kg. Lets say they also have 30 kg*m/s of momentum each. The small object would have 15 m/s velocity and the large would have 5 m/s.

Now for kinetic energy(.5*m*v²), the small object is .5*2*15², which is 225 J

The large object is .5*6*5², which is 75 J, so the smaller object has more Kinetic energy. Since velocity is squared, it is more important than how large mass is.

B) Same masses as part A. Lets say the kinetic energy is 45 J for both of them. For the small object, 45=.5*2*v²

.5*2 is 1, so 45/1 is 45. Take the square root and we get v= 6.71 m/s

For the large object, 45=.5*6*v²

.5*6 is 3, so 45/3 is 15. Take the square root and we get v=3.87 m/s

Now we plug the velocities into p=mv

For the small object, p=2*6.71, which gives us p=13.42 kg*m/s

For the large object, p=6*3.87, which gives us p=23.22 kg*m/s

The larger object has the larger momentum.

Hope this helps

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3 years ago

2. Anna mixes 200 g of hot coffee at 90 °C with 50 g of cold water at 3 °C to bring down the temperature of the coffee. Explain

natka813 [3]

The average kinetic energy of the molecules of the coffee will decrease and the speed of the individual molecules will also reduce.

<h3>Temperature of resultant mixture</h3>

The temperature of the resultant mixture will be higher than the cold water temperature and lower than the hot coffee temperature.

Based on the decrease of the resulting temperature (equilibrium temperature) of the mixture, the average kinetic energy of the molecules of the coffee will decrease and the speed of the individual molecules of the hot coffee mixture will reduce, leading to a resultant cold mixture of coffee.

Learn more about kinetic molecular model here: brainly.com/question/2901837

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2 years ago

Why might a plant that normally grows in one environment not grow well in a different one?

disa [49]

A plant that normally grows in one environment not grow well in a different environment because every flower is different around the certain providing environment.

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3 years ago

On a far-away (hypothetical) planet, a student is conducting an experiment to study vertical motion. The student fires a cannon

IgorC [24]

Yeah it’s pretty much positive

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3 years ago

(b) A Blu-ray laser has a power of 5 milliwatts (1 watt = 1 J s−1). How many photons of light are produced by the laser in 1 hou

worty [1.4K]

Answer:

The number of photons of light produced by the laser in 1 hour is

1 Photon / hour

Explanation:

Number of photons of light produced is given by

$Number of photons = \frac{Power}{Energy}$

From the question,

Power = 5 mW (milliwatts) = 5 × 10⁻³ W

Since 1 Watt = 1 Js⁻¹

Then, 5 × 10⁻³ W = 5 × 10⁻³ Js⁻¹

For the Energy,

As given from the question

Energy=(Power)x(time)

Time = 1 hour = (1 × 60 × 60) s = 3600 s

∴ Energy = 5 × 10⁻³ Js⁻¹ x 1 x 3600s

Energy =18.0 J

Now for the Number of photons produced,

$Number of photons = \frac{Power}{Energy}$

Power = 5 × 10⁻³ Js⁻¹ = 0.005 Js⁻¹

$Number of photons = \frac{0.005}{18}$

Number of photons = 2.78 × 10⁻⁴ Photons / sec

This is the number of photons produced in 1 second.

For the number of photons produced in 1 hour, we will multiply the result by 3600

(NOTE: 1 sec = $\frac{1}{3600}$ hour)

Number of photons = 2.78 × 10⁻⁴ Photons / sec

= 2.78 × 10⁻⁴ × 3600 Photons / hour

= 1.0008 Photons / hour

≅ 1 Photon / hour

Hence, the number of photons of light produced by the laser in 1 hour is

1 Photon / hour

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3 years ago