what role do control groups play

Answer:

Explanation:

If Two cylindrical resistors are made from the same material, then their resistivity will be the same.  Formula for calculating resistivity of a material is expressed as;

[tex]\rho = \frac{RA}{L} \ where \ A = \frac{\pi d^2}{4}[/tex] where;

R is the resistance

A is the cross sectional area of the material

L is the length of the material

For the shorter cylinder:

Length = L

diameter = D

[tex]\rho = \dfrac{R_s(\frac{\pi D^2}{4})}{L} \\\\\rho = \dfrac{R_s{\pi D^2}}{4L}[/tex]

For the longer cylinder:

Length = 16L

diameter = 4D

[tex]\rho = \dfrac{R_l(\frac{\pi (4D)^2}{4})}{16L} \\\\\\\rho = \dfrac{R_l(\frac{\pi (16D^2)}{4})}{16L} \\\\\rho = \dfrac{R_l{16\pi D^2}}{16L}\\\\\rho = \dfrac{R_l{\pi D^2}}{L}[/tex]

Since their resistivity are the same then;

[tex]\dfrac{R_s{\pi D^2}}{4L} = \dfrac{R_l{\pi D^2}}{L} \\\\ \dfrac{R_s}{4} = {R_l} \\\\R_s = 4R_l\\\\R_l = \frac{R_s}{4}[/tex]

Hence the resistance of the longer resistor is a quarter of the shorter resistor.

Answer:

This question appears incomplete

Explanation:

The question appears incomplete. However, a thrust can be described as a force or a push. A cart can be described as a vehicle (usually with two wheels) that is used to transport load from one point/place to another.

Newton first law of motion (law of inertia) states that a body will continue to be in a state of rest or if in motion, remains in motion (at constant velocity) unless acted upon by an external force. Hence, a cart will continue to be in a state of rest unless acted on by an external force which can be exerted by animals or humans (depending on the type of cart).

Answer:

3.0 x 10 and the exponent on ten is 5.

Explanation:

You are moving the decimal point over to the left 5 times, making the exponent a positive 5 and then you would put a decimal after 3. Making it 3.0 x 10, and the exponent 5.

The speed of x-rays in scientific notation is 3.0 x 10⁶ m/s.

The given parameters;

speed of the x-ray, v = 300,000 m/s

The standard form of the given number represents the scientific notation of the number.

In scientific notation the speed of the x-ray can be expressed as follows;

300,000 m/s = 3.0 x 10⁶ m/s

Thus, the speed of x-rays in scientific notation is 3.0 x 10⁶ m/s.

Learn more here: https://brainly.com/question/17093969

The best description of a gaseous substance is : (B). It has no definite shape or volume and will expand indefinitely.

A gaseous substance can be defined as a substance that is gaseous in nature or exhibit gaseous properties

A gaseous substance is just like a gas that its particles have unrestricted movement and the force of attraction between the particles are very weak or negligible.

In conclusion, The best description of a gaseous substance is : (B). It has no definite shape or volume and will expand indefinitely.

Learn more about gaseous substance: https://brainly.com/question/1771154

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Answer:

0.0552 m/s²

Explanation:

Given:

Δx = 69.0 m

v₀ = 0 m/s

t = 50 s

Find: a

Δx = v₀ t + ½ at²

69.0 m = (0 m/s) (50 s) + ½ a (50 s)²

a = 0.0552 m/s²

Answer:

A- 12 km

B- 42 minutes

C- 17.14 km per hour

Explanation:

A- The displacement of the total trip is 12 kilometers, which emerges by adding the 10 kilometers traveled by car to the 2 kilometers traveled on foot.

B- The trip, in total, took 42 minutes, which arises from adding the 30 minutes of the journey on foot, plus 12 minutes of travel by car at 72 km / h (72/60 x 10 = 12).

C- While 12 km were covered in 42 minutes, the average speed of the trip was 17.14 km / h. This arises from the following calculation:

42 = 12

60 = X

(60 x 12) / 42 = X

17.14 = X

Answer:

525 nm and 550nm

Explanation:

The absorption spectrum of any compound is a plot of absorption against wavelength. Sometimes, the absorption is plotted against frequency or wave number. This plot appears as humps. The peak of the highest hump is the wavelength of maximum absorption. The concentration of each solution may be indicated above the hump when the instrument is calibrated using different concentrations of the analyte.

The absorption spectrum of riboflavin indicates that its wavelength of maximum absorption is 450nm and it does not absorb at light 525 nm and 550nm wavelengths respectively.

Answer:

8125

Explanation:

[tex]P=0,13 N\\a=1,6 N/kg\\m=P/a=0,13/1,6=0,08125\\V=10(cm)^{3} =10^{-5} meters^{3} \\p=m/V=0,08125/10^{-5} =0,08125*100000=8125kg/meters^{3}[/tex]

Answer:

i actually dont know im so sorry but i will keep trying to find the answerr

Answer:

Explanation:

The question is incomplete. Here is the complete question.

A ball with mass m kg is thrown upward with initial velocity 22 m/s from the roof of a building 17 m high. Neglect air resistance. Use g=9.8 m/s2. Round your answers to one decimal place. (a) Find the maximum height above the ground that the ball reaches. xmax= meters (b) Assuming that the ball misses the building on the way down, find the time that it hits the ground.

a) Using the equation of motion formula;

v² = u²+2gH where;

u is the initial velocity

v is the final velocity

theta is the angle of launch

g is the acceleration due to gravity.

H is the maximum height reached by the ball

Since the ball is thrown upwards, the acceleration due to gravity will be negative. The equation then becomes;

v² = u²-2gH

Given

v = 0m/s

u = 22m/s

g = 9.8m.s²

0² = 22²-2(9.8)H

-22² = -19.6H

H = -22²/-19.6

H = 24.69m

If the biuliding is 17m high, the maximum height above the ground that the ball reaches will be;

Hmax = 24.69+17

Hmax = 41.69m

b) The time it takes to hit the ground can be expressed using the formula

v = u-gt

0 = 22-9.8t

-22 = -9.8t

t = -22/9.8

t = 2.45secs

The question is incomplete; However, the height from which the stone is thrown is most likely to be what's required of the question

Answer:

See Explanation

Explanation:

Given

[tex]Initial\ Speed, u = 12.0m/s[/tex]

[tex]Time, t = 1.54\ s[/tex]

Required

Determine the height

This question will be answered using the following equation of motion;

[tex]S = ut + \frac{1}{2}gt^2[/tex]

Take g as 9.8

This gives:

[tex]S = 12 * 1.54 + \frac{1}{2} * 9.8 * 1.54^2[/tex]

[tex]S = 12 * 1.54 + \frac{1}{2} * 9.8 * 2.3716[/tex]

[tex]S = 18.48 + 11.62084[/tex]

[tex]S = 30.10084[/tex]

[tex]S = 30.1\ m[/tex] (Approximated)

Hence; Height = 30.1m

Answer:

C- An explanation for why matter cannot be created or destroyed

Explanation:

Answer: A. A statement that matter cannot be created or destroyed.

Explanation:

Apex

Answer:

V=u+at

=4+4*2.5

=14m/s

Explanation:

Initial velocity =4m/s

acceleration =4m/(second) squared

time =2.5 seconds

v=u+at

v=4+4*2.5

v=14m/s

Answer:

This measurement would be a measure of the speed of an object(the car ) in motion

Explanation:

A driver looks down at their speedometer and sees they are moving at 45 mph. This measurement would be about the speed of the car or about how fast the car is moving.

This means, the car is travelling the distance of 45 miles in every hour.

This measurement would also be about the instantenous speed of the car which is 45mph.

Answer:

Resultant = 13km

Direction = 67.38° East of North

Explanation:

Given the following :

5km North ; 12km East

Resultant Displacement (r) :

r² = 5² + 12²

r² = 25 + 144

r² = 169

r = √169

r = 13

Direction:

Tangent = opposite / Adjacent

Tanθ = opposite / Adjacent

Opposite = 12 ; adjacent = 5

Tanθ = (12/5)

Tanθ = 2.4

θ = tan^-1(2.4)

θ = 67.38° east of north

Explanation:

Q1. Given:

v = 0 m/s

a = -5.5 m/s²

t = 3.5 s

Find: Δx

Δx = vt − ½ at²

Δx = (0 m/s) (3.5 s) − ½ (-5.5 m/s²) (3.5 s)²

Δx ≈ 33.7 m

Q2. Given:

Δx = 400 m

v₀ = 7.0 m/s

v = 35 m/s

Find: a

v² = v₀² + 2aΔx

(35 m/s)² = (7.0 m/s)² + 2a (400 m)

a = 1.47 m/s²

Answer:

15 m/s

Explanation:

We know that [tex]v = f * d[/tex] where f = frequency & d = wavelength .

So here.

Wavelength = 5 m

Frequency = 3 s⁻¹

Hence Speed = 5 * 3 = 15 m/s

Answer:

average acceleration is 1.365 × [tex]10^{4}[/tex] m/s²

Explanation:

given data

initila speed  u = -32.2 m/s

final speed v = 21.6 m/s

time taken t = 0.00394 s

solution

we get here average acceleration that will be express as

v = u + at    ..........................1

put here value and we get

21.6 = -32.2 + a × 0.00394

solve it we get

a = 1.365 × [tex]10^{4}[/tex] m/s²

so average acceleration is 1.365 × [tex]10^{4}[/tex] m/s²

Explanation:

did you upload a picture?

Answer:

18*10^10 meters

Explanation:

V= d/t         10 mins = 600 seconds

3*10^8 = d/600s

(3*10^8)*(6*10^2) = d

d = 18*10^10 m

Answer:

C. Tag the hummingbirds with transmitters and track their movement.

Explanation:

Hypothesis refers to the conclusion of the analysis found on the grounds of certain observations. The hypothesis is further tested and verified by performing certain experiments. In the given excerpt, Juan hypothesizes that certain group of hummingbirds fly to certain locations depending upon the season. To test the hypothesis, Juan can experiment with finding and tracking the hummingbirds and the direction in which they fly. Tagging the hummingbirds with transmitters and tracking their movement would help Juan concluding about the hypothesis.

Answer:

Tag the hummingbirds with transmitters and track their movement

Explanation:

Answer:

What is the difference between the electrons in the nucleus and the ones in orbit around the nucleus? ... The Strong Nuclear Force is an attractive force between protons and neutrons that keep the nucleus together and the Weak Nuclear Force is responsible for the radioactive decay of certain nuclei

Explanation:

The part B of the question is missing and it is;

b) What is the height between the two window ledges?

Answer:

A) 20.76 m/s

B) 161.52 m

Explanation:

A) To calculate the initial speed we use the formula from Newton's first law of motion:

v = u + at

Making u the subject gives;

u = v - at

Where;

v is the final velocity which is the speed when Jill sees the pot = 60 m/s

u is the initial velocity which is the speed when Jack sees the pot go by

t is the time between the two observed events = 4 s

a in this question is acceleration due to gravity = 9.81 m/s².

Plugging in the relevant values into the initial velocity equation gives;

u = 60 - (9.81 × 4)

u = 20.76 m/s

B) To get the height difference, we will use the formula;

(y1 - y0) = ut + ½at²

Thus, plugging in the relevant values, we have;

y1 - y0 = (20.76 × 4) + (½ × 9.81 × 4²)

(y1 - y0) = 161.52 m

Answer:

R = 52.08 cm

Explanation:

given data

tangential velocity v = 21.3 m/s

radial acceleration aR = 871 m/s²

solution

we will get here length of her arm from the pivot point at her shoulder so

here we know aR = [tex]\frac{v^2}{R}[/tex]     ........................1      

so put here value and we get

871 = [tex]\frac{21.3^2}{R}[/tex]  

R = 0.5208840 m

R = 52.08 cm

Answer:

Explanation:

linear speed of ball v = 21.3 m /s

radial acceleration = 871 m /s²

radial acceleration = v² / R

where R is length of arm which acts as radius of circular path of the ball .

Putting the values

21.3² / R = 871

R = .52 m.

Answer:

A. Dependent variable

Explanation:

In a graph showing how temperature of a material changes over time, temperature is taken on y-axis and time is taken on x-axis. It shows how temerature altered as the time changes.

In temperature-time graph, temperature is directly dependent on time. With the increase in time, temperature rises, falls or remains constant. It implies that temperature is dependent variable that depend on time.

Hence, the correct option is (A).

Answer:

The two forces acting on a boat or some other floating object are buoyancy and gravity

Answer: buoyant forceExplanation:two forces acting on a boat or some other floating object are buoyant force and gravityhi friend your answerI hope it will be helpful for you

mark as brainest answer

thank you

Answer:

16.7m/s

Explanation:

Using v= u+ at

V = final velocity. U = initial velocity

So since the two movements are the same they will return with the same speed they went up

Then final velocity v= 0

So

0:= u +-9.8 x 1.7

U= 16.7m/s

Answer:

[tex]2cos^2(\theta) - 1 = cos(2\theta)[/tex]

Explanation:

Given

[tex]2cos^2(\theta) - 1[/tex]

Required

Simplify

In trigonometry:

[tex]sin^2(\theta) + cos^2(\theta) = 1[/tex]

So; the given expression becomes

[tex]2cos^2(\theta) - (sin^2(\theta) + cos^2(\theta))[/tex]

Open Bracket

[tex]2cos^2(\theta) - sin^2(\theta) - cos^2(\theta)[/tex]

Collect Like Terms

[tex]2cos^2(\theta) - cos^2(\theta)- sin^2(\theta)[/tex]

[tex]cos^2(\theta)- sin^2(\theta)[/tex]

In trigonometry:

[tex]cos(\theta + \theta) = cos^2(\theta)- sin^2(\theta)[/tex]

This implies that:

[tex]cos^2(\theta)- sin^2(\theta) = cos(\theta + \theta)[/tex]

=

[tex]cos(\theta + \theta)[/tex]

[tex]cos(2\theta)[/tex]

Hence:

[tex]2cos^2(\theta) - 1 = cos(2\theta)[/tex]