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3 years ago

Will give brainlist!! Please help!!

Physics

1 answer:

kupik [55]3 years ago

6 0

Answer:

microwave, visible light, and radio waves.

Explanation:

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A railroad car moves under a grain elevator at a constant speed of 3.20 m/s. Grain drops into the car at the rate of 240 kg/min.

dedylja [7]

Answer:

F = 768 N

Explanation:

It is given that,

Speed of the elevator, v = 3.2 m/s

Grain drops into the car at the rate of 240 kg/min, $\dfrac{dm}{dt}=240\ kg/min = 4\ kg/s$

We need to find the magnitude of force needed to keep the car moving constant speed. The relation between the momentum and the force is given by :

$F=\dfrac{dp}{dt}$

$F=m\dfrac{dv}{dt}+v\dfrac{dm}{dt}$

Since, the speed is constant,

$F=m\dfrac{dv}{dt}$

$F=v\dfrac{dm}{dt}$

$F=3.2\times 240$

F = 768 N

So, the magnitude of force need to keep the car is 768 N. Hence, this is the required solution.

5 0

3 years ago

A vat of nitrogen at its boiling point (-196 degrees C) absorbs 384000 J of heat. How much mass of nitrogen burns off? (Unit = k

masya89 [10]

Answer:

1.92 kg of nitrogen.

Explanation:

The following data were obtained from the question:

Heat absorbed (Q) = 384000 J

Note: Heat of vaporisation (ΔHv) of nitrogen = 5600 J/mol

Next, we shall determine the number of mole of nitrogen that absorbed 384000 J.

This is illustrated below:

Q = mol·ΔHv

384000 = mole of N2 x 5600

Divide both side by 5600

Mole of N2 = 384000/5600

Mole of N2 = 68.57 moles

Next, we shall convert 68.57 moles of nitrogen, N2 to grams.

This can be obtained as follow:

Molar mass of N2 = 2 x 14 = 28 g/mol.

Mole of N2 = 68.57 moles.

Mass of N2 =..?

Mole = mass /molar mass

68.57 = mass of N2 /28

Cross multiply

Mass of N2 = 68.57 x 28

Mass of N2 = 1919.96 g

Finally, we shall convert 1919.96 g to kilograms.

This can be achieved as shown below:

1000g = 1 kg

Therefore,

1919.96 g = 1919.96/1000 = 1.92 kg.

Therefore, 1.92 kg of nitrogen were burned off.

3 0

3 years ago

What are the 2 types of crystallization ?

irinina [24]

Answer:

evaporative crystallization

cooling crystallization from solution or the melt

5 0

2 years ago

Read 2 more answers

Four students measured the same line with a ruler like the one shown below. The results were as follows: 5.52 cm, 6.63 cm, 5.5,

finlep [7]

Answer:

correct answer is 1 and 3

Explanation:

In direct measurement with an instrument, the precision or absolute error of the instrument is given by its appreciation, in this case we see that the measurements have two decimal places, so the appreciation of the instrument must be 0.01 cm

Based on this appreciation, the valid measurements are 5.52 and 5.5.

the other two measurements have errors much higher than the assessment of the instrument, for which there must have been some errors in the measurement.

The correct answer is 1 and 3

6 0

3 years ago

A cricket ball is dropped from a height of 20 m. Calculate: a) the speed of the ball. b) the time it takes to fall through this

AysviL [449]

Answer:

Initial velocity is 0 .. ( since it is just dropped)

now using V²= u² +2gh

=> (Vfinal)² = 0+2*10*20

=> v² = 20*20 = 400

=> v = √400 = 20m/s

for time taken

use V = u+gt

=> t = V/g = 20/10 = 2sec

7 0

2 years ago