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3 years ago

Which of the following is not good conductor of electricity

Physics

2 answers:

Anon25 [30]3 years ago

7 0

Answer:

Plastic is not a good conductor of electricity.

Explanation:

Hope it helps!

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Greeley [361]3 years ago

5 0

Answer:

where' s the choices??, because u say which of the following

Explanation:

HAHHA CLEAR YOUR QUESTION FIRST.

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A car moving at 10 m/s approaches a hill. If the car were put in neutral, it would roll up the hill to a stop at a certain eleva

dmitriy555 [2]

Answer:

They will not stop at same elevation

for v=10m/2 => h=5.1m

for v=20m/2 => h=20.4m

Explanation:

If we neglect the effects of friction in the calculations the energy if the system must be conserved. The car energy can be described as a combination of kinetic energy and potential energy:

$E=K+P$

The potential energy is due to the gravitational forces and can be describes as:

$P=g*h*m$

Where g is the gravitation acceleration, m the mass of the car, and h the elevation. This elevation is a relative quantity and any point of reference will do the work, in this case we will consider the base of the hill as h=0.

The kinetic energy is related to the velocity of the car as:

$K=1/2*m*v^{2}$

As the energy must be constant E will be always constant, replacing the expressions for kinetic and potenctial energy:

$E=1/2*m*v^{2}+g*h*m$

In the base of the hill we have h=0:

$E_{base} =1/2*m*v^{2}$

When the car stops moving we have v=0:

$E_{top} =g*h_{top}*m$

This two must be equal:

$E_{base} =E_{top}$

$1/2*m*v^{2} =g*h_{top}*m$

solving for h:

$h_{top} =\frac{v^{2}}{2*g}$

Lets solve for the two cases:

for v=10m/2 => h=5.1m

for v=20m/2 => h=20.4m

As you can see, when the velocity is the double the height it reaches goes to four times the former one.

3 0

3 years ago

A golf ball flies through the air after being struck with a golf club. Which of the following statements describes the force on

valentina_108 [34]

Answer:

C) The force experienced by the ball equals the force experienced by the club.

Explanation:

When the golfer strikes the ball with his club, the club exerts a force on the ball. Due to Newton's Third Law Of Motion [Every Action has an equal and opposite reaction], the ball also exerts an equal force on the club. However,

As the mass of the club is usually greater than the mass of the ball, it accelerates slower; While the ball way faster, following the equation : F=ma

3 0

3 years ago

Can 200 watts lift a 100 kg box,and if so how long would it take?

topjm [15]

The only definite number we can tell you is that in order to lift
a 100kg box, you have to somehow provide a force of about
980 newtons (about 220 pounds) pointing upward. That's the
weight of the box, and you have to lift with at least that much force
just to get the box off the ground.

After that, the answer to your question is 'YES'. The time it takes
depends on how much force you have available, how far you want
to lift the box, and how fast.

Here are the Physics formulas you have to use:

-- The amount of "Work" you'll do is

(the amount of force you use) times (how far up you lift the box) .

-- The "Power" (amount of watts) you'll use is

(the amount of 'work' you do) divided by (the length of time it takes).

So ...

-- The higher you lift the box, the more 'work' your lift-machine does.

-- The faster the box is lifted, the more 'power' your lift-machine needs.

4 0

3 years ago

Please help

Sergio039 [100]

2) The velocity of the wheel is increasing

3) The slope is the rate of change of velocity

4) The unit of the slope is metres per second squared.

5) Acceleration

6) The symbol used for acceleration is $a$

7) The relationship between velocity and time is $v=gsin \theta t$

Explanation:

The graph in the problem represents the velocity of the wheel as a function of the time.

As we can see from the graph, the velocity is increasing as the time passes. This means that the wheel is accelerating (its velocity is changing constantly)

The slope of the graph represents the rate of change of the velocity.

Mathematically, it can be written as:

$m=\frac{\Delta v}{\Delta t}$

where

m is the slope

$\Delta v$ is the change in velocity

$\Delta t$ is the time interval considered

As we see from the graph, the slope of the line is positive and constant: this means that the velocity is increasing at a constant rate.

The unit of the slope can be determined starting by the units of the two variables involved.

On the y-axis, we have the velocity, which is measured in metre per second ( $m/s$ )

On the x-axis, we have the time, which is measured in seconds ( $s$ )

The slope is the ratio between these two quantities:

$m=\frac{\Delta v}{\Delta t}$

Therefore, the units of the slope are

$m=\frac{[m/s]}{[s]}=[m/s^2]$

So, metres per second squared.

The rate of change of velocity is also known as acceleration.

In fact, acceleration is defined as the ratio between the change in velocity and the change in time:

$a=\frac{\Delta v}{\Delta t}$

By comparing with the formula of the slope in part 3), we see that the two equations are identical, therefore the acceleration corresponds to the slope of the graph.

The symbol used to represent the acceleration is $a$ :

$a=\frac{\Delta v}{\Delta t}$

In any uniformly accelerated motion, the relationship between velocity and time is given by the following suvat equation:

$v=u+at$

where

u is the initial velocity

v is the final velocity

a is the acceleration

t is the time

In this problem, the wheel starts from rest, so

u = 0

Also, for an object rolling down a ramp, the acceleration is given by

$a=g sin \theta$

where g is the acceleration of gravity and $\theta$ is the angle of the ramp. Substituting, we find the final expression of the velocity:

$v=gsin \theta t$

Learn more about acceleration:

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8 0

3 years ago

Two stars are 3.7 1011

dem82 [27]

Answer:

L = 5.68 10¹⁷ m

Explanation:

The resolution of the telescope is given by diffraction

a sin θ = m λ

Where a is the separation of the linear slits, λ the wavelength, m an integer that determines the order of diffraction

In this case, suppose that the premieres meet Rayleigh's criteria, which establishes that the central maximum of the diffraction of an object coincides with the first minimum of diffraction of the second object. In this case m = 1

sin θ = λ / a

In the case of circular openings, polar coordinates must be used, so the equation is

sin θ = 1.22 λ / D

Where D is the diameter of the lens or tightness. Since the distances are very large and the small angles we can approximate the sine to the radian angle value

θ = 1.22 λ / D

Let's use trigonometry to find the angle. We have the separation of the premieres y = 3.7 10¹¹ m and

tan θ = y / L

θ = y / L

Let's replace

y / L = 1.22 λ / D

L = y D / 1.22 λ

calculate

L = 3.7 10¹¹ 1.03 / (1.22 550 10⁻⁹)

L = 5.68 10¹⁷ m

8 0

3 years ago

Which of the following is not good conductor of electricity​

Which of the following is not good conductor of electricity