An elevator held by a single cable is ascending but slowing down. Is the work done by tension positive, negative, or zero? What about the work done by gravity? Explain

Answer:

B

Explanation:

The answer should be B.

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

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:

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:

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:

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:

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:

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:

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:

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:

The answer is

Explanation:

To calculate the work done by a body we use the formula

From the question

force = 10 N

distance covered = 1.5 m

So the work done is

work done = 10 × 1.5

We have the final answer as

Hope this helps you

Answer:

The magnetic field is zero at a radius r = 4 cm.

Explanation:

The magnetic field due to the wire is given by B₁ = μ₀I₁/2πr where I₁ = current in wire = 1 A and r = distance of point where magnetic field is zero from wire.

Now, since the current is uniformly distributed in the cross section of the cylinder, its current density is constant.

So, with current I₂ = 9 A flowing in the cylinder and radius, a = 12 cm. Let I' = current at radius r where the magnetic field is zero. So,

I'/πr² = I₂/πa²

I' = I₂r²/a²

Using Ampere's Law, the magnetic field B₂ at the distance r is given by

∫B.ds = μ₀I'

∫Bdscos0 = μ₀I' (since the magnetic field is parallel to the path)

B∫ds = μ₀I'   ∫ds  = 2πr

B2πr = μ₀I'

2Bπr = μ₀I₂r²/a²

B₂ = μ₀I₂r/2πa²

So, when the net magnetic field is zero, B₁ = B₂

So,  μ₀I₁/2πr = μ₀I₂r/2πa²

I₁/r = I₂r/a²

I₁/I₂ = r²/a²

r² = I₁/I₂a²

taking square root of both sides,

r = a√(I₁/I₂)

substituting the values of the variables, we have

r = 12√(1/9)

r = 12/3

r = 4 cm

The magnetic field is zero at a radius r = 4 cm.

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:

The hight of the building is 38.16 m

Explanation:

These two pieces of information given, first, the watermelon is 30 m  above the ground and after 1.50 s the watermelon has been spotted. Now we are required to find the height of the building.

Use the below formula to find the height of buildings.

S = ut + ½ gt^2

30  =1.5u + (1/2) × 9.8 (1.5)^2

u = 12.65 m/sec

v^2 – u^2 = 2gs

(12.65)^2 = 2×9.8 s’

S’ = 8.16 m  

h = s + s’

h = 30 + 8.16 = 38.16 m

The hight of the building is 38.16 m.

The height of the building is 38.16 m.

Given data:

The height above the ground is, h = 30.0 m.

The time interval after observation of first spot is, t = 1.50 s.

We need to find the height of building. And since two pieces of information given, first, the watermelon is 30 m  above the ground and after 1.50 s the watermelon has been spotted. So, using the second kinematic equation of motion as,

[tex]h = ut + \dfrac{1}{2}gt^{2}[/tex]

Here, u is the initial speed. Solving as,

[tex]30 = (u \times 1.50) + \dfrac{1}{2} \times 9.8 \times (1.50)^{2}\\\\u =12.65 \;\rm m/s[/tex]

Now landing distance (s') is calculated using the third kinematic equation of motion as,

[tex]v^{2} =u^{2}+2(-g)s\\\\0^{2} =12.65^{2}+2(-9.8)s\\\\s = 8.16 \;\rm m[/tex]

Then the height of building is given as,

H = h + s

H = 30 m + 8.16 m

H = 38.16 m

Thus, we can conclude that the height of the building is 38.16 m.

Learn more about the kinematic equations of motion here:

https://brainly.com/question/16556016

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

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

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:

Explanation:

a) because it's immoral as you're trying to convince people of your views when you should be giving both sides of the story so people are able to come up with their own opinions on what you're talking about

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:

[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]

Answer:

1.73 m/s²

Explanation:

Given:

Δx = 250 m

v₀ = 0 m/s

t = 17 s

Find: a

Δx = v₀ t + ½ at²

250 m = (0 m/s) (17 s) + ½ a (17 s)²

a = 1.73 m/s²

The acceleration of this object is 1.730 meter per seconds square.

Given the following data:

To find the acceleration of this object, we  would use the second equation of motion.

Mathematically, the second equation of motion is given by the formula;

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

Where:

Substituting the given values into the formula, we have;

[tex]250 = 0(17) + \frac{1}{2} (a)(17^2)\\\\250 = \frac{1}{2} (289)a\\\\250 = 144.5a\\\\a = \frac{250}{144.5}[/tex]

Acceleration, a = 1.730 [tex]m/s^2[/tex]

Therefore, the acceleration of this object is 1.730 meter per seconds square.

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Answer:

The new period will be reduced by 50%

Explanation:

The period of pendulum is given by;

[tex]T= 2\pi\sqrt{\frac{L}{g} }\\\\\frac{T}{2\pi} = \sqrt{\frac{L}{g} }\\\\(\frac{T}{2\pi} )^2 = {\frac{L}{g}}\\\\\frac{T^2}{4\pi ^2} = {\frac{L}{g}}\\\\T^2(\frac{g}{4\pi ^2}) = L\\\\ \frac{g}{4\pi ^2}= \frac{L}{T^2}\\\\\frac{L_1}{T_1^2} = \frac{L_2}{T_2^2}[/tex]

When the length is decreased by 25%, the new length L₂ is given by;

L₂ = 25/100(L₁)

L₂ = 0.25L₁

[tex]\frac{L_1}{T_1^2} = \frac{L_2}{T_2^2}\\\\T_2^2 = \frac{T_1^2L_2}{L_1} \\\\T_N^2 = \frac{T^2(0.25L_1)}{L_1}\\\\ T_N^2 =0.25T^2\\\\T_N = \sqrt{0.25T^2}}\\\\T_N = 0.5 T[/tex]

Thus, the new period will be reduced by 50%

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:

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:

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:

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:

18.3 C

Explanation:

Answer: 55/3 °C

Explanation:

Formula:

C=5/9(F-32)

Given:

F=65

Solve:

C=5/9(F-32)

C=5/9(65-32)

C=5/9(33)

C=55/3

Answer:

We use pythagorean theorem

So that

r = √(x² + y²)

r = √(94.8)² + (-149)² )

r =√ 9682.6 + 22201

= 178.6

direction we use

စ = tan^-1(98.4/149)

= tan^-1 (0.6604)°