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3 years ago

22 POINTS!!PLEASE HELP

1 answer:

8 0

Method of decreasing friction:By polishing: Friction between two surfaces can be reduced by polishing them. The interlocking and projections are minimized by this method.

Ball-bearing: As the rolling friction less than the sliding friction consequently in rotating machinery, the shafts are fixed on the ball bearing so that the friction can be reduced considerably. For example-the free wheel of a cycle, the axle of a motorcar, the shafts of the motor dynmo etc. are provided with ball-bearing.

Lubricants: Friction between two surfaces can be decreased by using lubricants. A lubricant is a substance (a solid or a liquid) which forms a thin layer between the two surfaces in contact. It also fills the depressions present in the surfaces of contact and reduces friction considerably. In light machinery thin oils with low viscosity are used, in heavy and fast moving machinery thick oils and solutes (grease) are used.
Streamline: The friction due to air is reduced by making the automobiles streamline.

Methods of increasing friction:By making the surface rough friction can be increased. Examples of increasing friction-the tires of a motor car and bicycles are made rough to increase the friction .when a ground or surface become slippery after rain or water splashing it is made rough by spreading sand to increase the friction.

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Cassie is an engineering undergrad. She does not like talking much, and has become a quiet and withdrawn person while in her pro

stepan [7]

Answer:

Explanation:

Analytical people are less responsive to others. They hence tend to focus more on work than people and are less interested in leading, being happier to work by themselves. They may be prudent and systematic, making them good at analytic work.

Some character traits of Analytical people

Focuses on work and working more than people

Likes to be correct and will take time to ensure this

Thoughtful, careful fact-oriented and precise

Good at problem-solving

Likes organization and structure

Avoids working in a group, preferring to work alone

Can be over-critical and unresponsive

Cautious in decision-making

When stressed may withdraw or become headstrong

8 0

3 years ago

3. A cat pushes a 0.25-kg toy with a net force of 8 N. According to Newton's second

jek_recluse [69]

Mass=0.25kg
Force=8N

$\\ \sf{:}\!\implies F=ma$

$\\ \sf{:}\!\implies Acceleration=\dfrac{F}{m}$

$\\ \sf{:}\!\implies Acceleration=\dfrac{8}{0.25}$

$\\ \sf{:}\!\implies Acceleration=32m/s^2$

5 0

3 years ago

A physicist drives through a stop light. When he is pulled over, he tells the police officer that the Doppler shift made the red

Alik [6]

Answer:

Speed of physicist car is 0.036c or 1.08 x 10⁷ m/s .

Explanation:

Doppler Effect is defined as the change in frequency or wavelength of the wave as the source or/and observer moving away or towards each other.

In this case, the Doppler effect equation in terms of wavelength is :

$\lambda_{s} = \lambda_{o}\sqrt{\frac{1-\frac{v}{c} }{1+\frac{v}{c} } }$ ......(1)

Here $\lambda_{s}$ is source wavelength, $\lambda_{o}$ is observed wavelength, v is speed of the observer and c is the speed of light.

Given :

Source wavelength, $\lambda_{s}$ = 660 nm = 660 x 10⁻⁹ m

Observed wavelength, $\lambda_{0}$ = 555 nm = 555 x 10⁻⁹ m

Substitute these values in the equation (1).

$555\times10^{-9} } = 660\times10^{-9} \sqrt{\frac{1-\frac{v}{c} }{1+\frac{v}{c} } }$

$\sqrt{\frac{1-\frac{v}{c} }{1+\frac{v}{c} } } = 0.84$

${\frac{1-\frac{v}{c} }{1+\frac{v}{c} } } = (0.84)^{2} = 0.7056$

$1-\frac{v}{c}=0.7056+0.7056\frac{v}{c}$

$\frac{v}{c}=\frac{0.2944}{8.056}$

$v = 0.036c=0.036\times3\times10^{8}$

v = 1.08 x 10⁷ m/s

8 0

3 years ago

Unpolarized light with an average intensity of 845 W/m2 enters a polarizer with a vertical transmission axis. The transmitted li

RideAnS [48]

The concept to develop this problem is the Law of Malus. Which describes what happens with the light intensity once it passes through a polarized material.

Mathematically this can be expressed as

$I = I_0 cos^2\theta$

Where

I = New intensity after pass through the Polarizer

$I_0$ = Original intensity

$\theta$ = Indicates the angle between the axis of the analyzer and the polarization axis of the incident light.

When the light passes perpendicularly through the first polarizer, the light intensity is reduced by half which will cause the intensity to be $225W / m ^ 2$ at the output of the new polarizer, mathematically:

$I= \frac{I_0}{2} cos^2\theta$

$225 = \frac{845}{2}cos^2\theta$

Solving to find the angle we have

$\theta = 43.11\°$

The orientation angle of the second polarizer relative to the first one is 43.11°

5 0

3 years ago

In 10 seconds a car accelerates 4/ms to 60m/s. how fast was the car going before it accelerated?

SVETLANKA909090 [29]

Well it seems like this problem gives you what you need. You said the car was going 4m/s and then accelerated to 60m/s... so 4m/s would be your answer for the initial velocity

6 0

2 years ago

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