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3 years ago

5 ways in which friction can be useful

1 answer:

6 0

Friction can be useful when you trying to stop a car, also it can be useful in energy losses, increase wear and tear and produces heat

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What is the relationship between thermal energy, temperature, pressure?

Ira Lisetskai [31]

Answer: When volume is constant, pressure is directly proportional to temperature. When temperature is constant, pressure is inversely proportional to volume. When pressure is constant, volume is directly proportional to temperature.

Explanation:

6 0

3 years ago

Which of the following situations would cause the greatest decrease in the motion of molecules in a system

Yakvenalex [24]

At 0 Kelvin everything stops moving ( even electrons ), so you could try to decrease the system's temperature
0 Kelvin = -273 Celsius

3 0

3 years ago

Two closed containers look the same but when is packed with LED and the other with a few feathers how could you determine which

Rudik [331]

You would want to push both containers, first one and then the other,
with exactly the same strength of push.

The one that takes off slower (with less acceleration from the same
net force) is the one with more mass.

3 0

3 years ago

Read 2 more answers

Suppose you have an unknown clear substance immersed in water, and you wish to identify it by finding its index of refraction. Y

s344n2d4d5 [400]

Answer: 1.65

Explanation: Snell's law says that index of refraction of the first material times sine theta one equals index of refraction of the second material, which we don't know, multiplied by sine theta two, . So, we'll solve this for N two by dividing both sides by sine theta two. So, N two is N one sine theta one over sine theta two . So, that's 1.33 index of refraction of water times sine of 45.7degrees incidence angle divided by sine of 30.5 degrees angle of refraction, giving us 1.65.

The formula for snell's law is N1*sintheta1=N2*sinetheta2

3 0

3 years ago

An object of mass 30KG is falling in air and experiences a force due to air resistance of 50 newtons determine the net force act

ryzh [129]

Answer:

Assume that $g = 10\; \rm N \cdot kg^{-1}$ . The net force on this object will be $250\; \rm N$ (downwards.) The acceleration of this object will be approximately $8.3\; \rm m \cdot s^{-2}$ (also downwards.)

Explanation:

<h3>Net force</h3>

The object is falling towards the ground because of gravity. The size of the gravitational force on this object depends on its mass and the strength of the gravitational field at its location.

Near the surface of the earth, the gravitational field strength is approximately $10\; \rm N \cdot kg^{-1}$ . In other words, approximately $10\; \rm N$ of gravitational force acts on each kilogram of mass near the surface of the earth.

The mass of this object is given as $m = 30\; \rm kg$ . Therefore, the size of the gravitational force on it will be:

$W = m \cdot g \approx 30 \; \rm kg \cdot 10\; N \cdot kg^{-1} = 300\; \rm N$ .

Near the surface of the earth, gravitational forces point towards the ground. On the other hand, the direction of air resistance on this object will be opposite to its direction of motion. Since this objects is moving towards the ground, the air resistance on it will be directed in the opposite direction. That's exactly the opposite of the direction of the gravitational force on this object. The net force on this object will be:

$300\; \rm N - 50\; \rm N =250\; \rm N$ .

<h3>Acceleration</h3>

Let $a$ denote the acceleration on this object. Apply Newton's Second Law of motion:

$\begin{aligned} a &= \frac{F(\text{net force})}{m} \approx \frac{250\; \rm N}{30\; \rm kg} \approx 8.3\; \rm m \cdot s^{-2}\end{aligned}$ .

Note that the acceleration of this object and the net force on it should be in the same direction.

8 0

3 years ago