1. What is the average speed of a runner that<br> travels 100 meters in 9.7 seconds?

The electric potential at the dot in the figure is 3160 V. What is charge q?

PSYCHO15rus [73]

Hi there!

Recall the equation for electric potential of a point charge:

$V = \frac{kQ}{r}$

V = Electric potential (V)
k = Coulomb's Constant(Nm²/C²)

Q = Charge (C)
r = distance (m)

We can begin by solving for the given electric potentials. Remember, charge must be accounted for. Electric potential is also a SCALAR quantity.

Upper right charge's potential:

$V = \frac{(8.99*10^9)(-5 * 10^{-9})}{0.04} = -1123.75 V$

Lower left charge's potential:

$V = \frac{(8.99*10^9)(5*10^{-9})}{0.02} = 2247.5 V$

Add the two, and subtract from the total EP at the point:

$3160 + 1123.75 - 2247.5 = 2036.25$

The remaining charge must have a potential of 2036.25 V, so:

$2036.25 = \frac{(8.99*10^9)(Q)}{\sqrt{0.02^2 + 0.04^2}}\\\\2036.25 = \frac{(8.99*10^9)Q}{0.0447} \\\\Q = 0.000000010127 = \boxed{10.13nC}$

5 0

2 years ago

A car is to be hoisted by elevator to the fourth floor of a parking garage, which is 48 ft above the ground. If the elevator can

belka [17]

Answer: 21.91 s

Explanation:

Given that,

Maximum height of the car, h = 48 ft

Acceleration of the elevator, a = 0.6 ft/s²

Deceleration of the elevator, -a = 0.3 ft/s²

Maximum speed of the elevator, v = 8 ft/s

Initial speed of the elevator, u = 0

If when the elevator accelerate from 0 to maximum velocity, v.

Let s be the vertical distance traveled during acceleration.

v² = u² - 2as

s = (v² - u²) / 2a

s = (8² - 0) / 2*0.6

s = 64 / 1.2

s = 53.33 ft

If when the elevator decelerates from maximum velocity, v to zero.

Let S be the vertical distance traveled during deceleration

u² = v² + 2aS

S = (u² - v²) / 2a

S = (0 - 8²) / 2 * 0.3

S = -64 / 0.6

S = 106.67 ft

Since he sum of s and S (i.e s + S) is greater than 48 ft, then the elevator will switch from acceleration to deceleration

without reaching the maximum velocity. Below, the switching point is labeled y.

v² = u² + 2ay

y = v²/2a

Inserting this into the earlier deceleration equation, we have

-v²/2 = d * [48 - (v²/2a)], where

d = deceleration

a = acceleration

Therefore, v = [4.√6. a √-(a.b/a)] / b

Where b = acceleration - deceleration

v = 4.382 ft/s

Using this newly found v, we proceed to find our s

s = (u² + v²)/2a

s = 19.2 / 1.2

s = 16 ft

The transport times for each segment are found from

v = u + a*t, thus upward t1

4.382 = 0 + 0.6 * t

t = 4.382/0.6

t = 7.303 s

Also,

4.382 = 0 + 0.3 * T

T = 4.382/0.3

T = 14.607 s

The total travel time is then t + T =

7.303 + 14.607

Total time of travel is 21.91 s

5 0

3 years ago

A scientist notices that an oil slick floating on water when viewed from above has many different rainbow colors reflecting off

Semenov [28]

Answer:

Explanation:

In case of oil slick a thin layer of oil is formed on water . This thin layer creates a rainbow of colour . The phenomenon is due to interference of light waves , one reflected from the upper surface of oil and the other reflected from the lower surface of the oil.

For formation of bright colour

2 μ t = ( 2n + 1 ) λ / 2

μ is refractive index of oil , t is thickness of oil layer λ is wave length of light falling on the layer .

given μ = 1.2 , λ = 750 x 10⁻⁹ ,

2 x 1.2 t = ( 2n + 1 ) 750 x 10⁻⁹ / 2

For minimum thickness n = 0

2.4 t = 375 x 10⁻⁹

t = 156.25 n m

B ) If the refractive index of layer of medium below oil is less than that of oil , the condition of formation of colour changes

The new condition is

2 μ t = n λ

2 x 1.5 t = 750 nm , n = 1 for minimum wavelength .

t = 250 nm

C ) Light mostly transmitted means dark spot is formed at that point .

For that to be observed from water side , the condition is

2 μ t = ( 2n + 1 ) λ / 2

λ = 4μ t / ( 2n + 1 )

For maximum wavelength n = 0

λ = 4μ t

= 4 x 1.5 x 200 nm

= 1200 nm .

3 0

3 years ago

With the aim of a diagram describe how a rain bow is formed

Natalija [7]

Answer:

Water droplets acts as tiny prism in the sky. The sunlight when enters these tiny droplets undergo internal reflection and also refract these rays which are dispersed causing a band of seven colors called rainbow.

Explanation:

3 0

2 years ago

Read 2 more answers

Four complete waves pass the duck in one second the frequency of this wave is

galben [10]

The frequency of a wave is the number of complete oscillations passing a given point per second.

In this case, assuming the duck is stationary, we have 4 complete waves passing the duck in one second: therefore, the frequency of the wave is
$f= \frac{4}{1 s}=4 Hz$

3 0

3 years ago

1. What is the average speed of a runner that travels 100 meters in 9.7 seconds?