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3 years ago

What is the main reason why people use machines

Physics

2 answers:

Butoxors [25]3 years ago

5 0

Answer:

Machines are faster and more efficent

Explanation:

vova2212 [387]3 years ago

3 0

Answer: Machines makes work easier and save some time and is very fast. For example, an elder can't walk or stand very long, so people made a motorized wheelchair!

Explanation:

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A car travels at a steady 40.0 m/s around a horizontal curve of radius 200 m. What is the minimumcoefficient of static friction

zhenek [66]

Answer:

c. 0.816

Explanation:

Let the mass of car be 'm' and coefficient of static friction be 'μ'.

Given:

Speed of the car (v) = 40.0 m/s

Radius of the curve (R) = 200 m

As the car is making a circular turn, the force acting on it is centripetal force which is given as:

Centripetal force is, $F_c=\frac{mv^2}{R}$

The frictional force is given as:

Friction = Normal force × Coefficient of static friction

$f=\mu N$

As there is no vertical motion, therefore, $N=mg$ . So,

$f=\mu mg$

Now, the centripetal force is provided by the frictional force. Therefore,

Frictional force = Centripetal force

$f=F_c\\\\\mu mg=\frac{mv^2}{R}\\\\\mu=\frac{v^2}{Rg}$

Plug in the given values and solve for 'μ'. This gives,

$\mu = \frac{(40\ m/s)^2}{200\ m\times 9.8\ m/s^2}\\\\\mu=\frac{1600\ m^2/s^2}{1960\ m^2/s^2}\\\\\mu=0.816$

Therefore, option (c) is correct.

7 0

4 years ago

(03.05 LC)<br> Which of the following best describes the use of a renewable resource

RUDIKE [14]

Answer:

Option C or the third option.

Explanation: Water is a renewable resource there is so much of it and it just keeps circulating through the system it doesn't run out.

6 0

4 years ago

Determine the angular speed, in rad/s of:

ryzh [129]

Answer:

Explanation:

A. The earth about its axis:

The earth makes one revolution in 24 hours. to know the number of revolutions per second it makes, we need to convert hours to seconds and the revolution to rad.

$\frac{1 rev}{24hours}\times \frac{1 hr}{3600s}\times \frac{2\pi}{1}= 7.27 \times10^-5 rad/s$

B. The minute hand of the clock makes one revolution in 60 minutes

To convert this to rad per second, we have

$\frac{1 rev}{60mins}\times \frac{1 min}{60s}\times \frac{2\pi}{1}= 1.745 \times10^-3rad/s$

C. The hour hand of a clock completes one revolution in 12 hours

$\frac{1 rev}{12hours}\times \frac{1 hr}{3600s}\times \frac{2\pi}{1}= 1.454 \times10^-4 rad/s$

D. an egg beater turning at 300 rpm.

$\frac{300 rev}{1minute}\times \frac{1 min}{60s}\times \frac{2\pi}{1}= 7.27 \times10^-5 rad/s=0.0218rad/s$

6 0

3 years ago

what happens to the volume when temperature is held constant and the pressure is increased to 125 kPa

Semenov [28]

The volume decreases, by a factor of

(the original pressure/(125 kPa).

5 0

3 years ago

What is the mass of an atom with seven protons.seven neutrons,and eight electrons?

soldier1979 [14.2K]

A nitrogen atom with 7 protons and 8 neutrons has a mass number of 15amu however on the periodic table the atomic mass for nitrogen is 14.01

3 0

3 years ago

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