1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Rina8888 [55]
2 years ago
5

A 70 ft rope hangs from a helicopter above this room. The rope has a mass per unit length of 2 lb/ft. In order to be rescued fro

m this exam the helicopter must pull you up and out of the room to safety. Assume that you weigh 120 lbs. How much work will it take get you safely away from this test
Physics
1 answer:
Mrac [35]2 years ago
4 0

Answer:

The work done to get you safely away from the test is  2.47 X 10⁴ J.

Explanation:

Given;

length of the rope, L = 70 ft

mass per unit length of the rope, μ = 2 lb/ft

your mass, W = 120 lbs

mass of the 70 ft rope  = 2 lb/ft x 70 ft

                                         = 140 lbs.

Total mass to be pulled to the helicopter, M = 120 lbs  + 140 lbs  

                                                                       = 260 lbs

The work done is calculated from work-energy theorem as follows;

W = Mgh

where;

g is acceleration due gravity = 32.17 ft/s²

h is height the total mass is raised = length of the rope = 70 ft

W = 260 Lb x 32.17 ft/s²  x 70 ft

W = 585494 lb.ft²/s²

1 lb.ft²/s² = 0.0421 J

W = 585494 lb.ft²/s²  = 2.47 X 10⁴ J.

Therefore, the work done to get you safely away from the test is  2.47 X 10⁴ J.

You might be interested in
Who is the father of electricity?
Tpy6a [65]
William Gilbert is known as the father of electricity.
7 0
3 years ago
Read 2 more answers
How could we expect a white paper to appear when viewed in a red light?
Xelga [282]
The accurate answer is:
You could expect a white paper to have a red tone when viewed in a red light. This is the case because of the neutrality of the white paper.
4 0
3 years ago
The smallest detail visible with ground-based solar telescopes is about 1 arc second. How large a region (in km) does this repre
mestny [16]

Answer:

x = 727.5 km

Explanation:

With the conditions given using trigonometry, we can find the tangent

       tan θ = CO / CA

With CO the opposite leg and CE is the adjacent leg which is the distance from the Tierral to Sun

   

        D =150 10⁶ km (1000m / 1 km)

        D = 150 10⁹ m.

We must take the given angle to radians.

       1º  = 3600 arc s  

       π rad = 180º

       θ = 1 arc s (1º / 3600 s arc) (pi rad / 180º) =

       θ = 4.85 10⁻⁶ rad

That angle is extremely small, so we can approximate the tangent to the angle

     

       θ = x / D

       x = θ D

       x = 4.85 10-6  150 109

       x = 727.5 103 m

       x = 727.5 km

4 0
3 years ago
What is the difference between the B-field and the H-field?
Simora [160]
The H field is in units of amps/meter.  It is sometimes called the auxiliary field. It describes the strength (or intensity) of a magnetic field. The B field is the magnetic flux density.  It tells us how dense the field is.  If you think about a magnetic field as a collection of magnetic field lines, the B field tells us how closely they are spaced together. These lines (flux linkages) are measured in a unit called a Weber (Wb).  This is the analog to the electric charge, the Coulomb.  Just like electric flux density (the D field, given by D=εE) is Coulombs/m²,  The B field is given by Wb/m², or Tesla.  The B field is defined to be μH, in a similar way the D field is defined.  Thus B is material dependent.  If you expose a piece of iron (large μ) to an H field, the magnetic moments (atoms) inside will align in the field and amplify it.  This is why we use iron cores in electromagnets and transformers.
So if you need to measure how much flux goes through a loop, you need the flux density times the area of the loop Φ=BA.  The units work out like 
Φ=[Wb/m²][m²]=[Wb], which is really just the amount of flux.  The H field alone can't tell you this because without μ, we don't know the "number of field" lines that were caused in the material (even in vacuum) by that H field.  And the flux cares about the number of lines, not the field intensity.
I'm way into magnetic fields, my PhD research is in this area so I could go on forever.   I have included a picture that also shows M, the magnetization of a material along with H and B.  M is like the polarization vector, P, of dielectric materials. If you need more info let me know but I'll leave you alone for now!

3 0
3 years ago
A miniature quadcopter is located at x = -2.25 m and y, - 5.70 matt - 0 and moves with an average velocity having components Vv,
kupik [55]

Recall that average velocity is equal to change in position over a given time interval,

\vec v_{\rm ave} = \dfrac{\Delta \vec r}{\Delta t}

so that the <em>x</em>-component of \vec v_{\rm ave} is

\dfrac{x_2 - (-2.25\,\mathrm m)}{1.60\,\mathrm s} = 2.70\dfrac{\rm m}{\rm s}

and its <em>y</em>-component is

\dfrac{y_2 - 5.70\,\mathrm m}{1.60\,\mathrm s} = -2.50\dfrac{\rm m}{\rm s}

Solve for x_2 and y_2, which are the <em>x</em>- and <em>y</em>-components of the copter's position vector after <em>t</em> = 1.60 s.

x_2 = -2.25\,\mathrm m + \left(2.70\dfrac{\rm m}{\rm s}\right)(1.60\,\mathrm s) \implies \boxed{x_2 = 2.07\,\mathrm m}

y_2 = 5.70\,\mathrm m + \left(-2.50\dfrac{\rm m}{\rm s}\right)(1.60\,\mathrm s) \implies \boxed{y_2 = 1.70\,\mathrm m}

Note that I'm reading the given details as

x_1 = -2.25\,\mathrm m \\\\ y_1 = -5.70\,\mathrm m \\\\ v_x = 2.70\dfrac{\rm m}{\rm s}\\\\ v_y=-2.50\dfrac{\rm m}{\rm s}

so if any of these are incorrect, you should make the appropriate adjustments to the work above.

8 0
3 years ago
Other questions:
  • A 3.92 cm tall object is placed in 31.3 cm in front of a convex mirror. The focal
    12·1 answer
  • How are moving pulleys different from fixed-position pulleys? (Points : 3) Moving pulleys have more force than fixed-position pu
    5·2 answers
  • 3 kg of wet clothes are hung on the middle of a clothesline with posts 6 ft apart. The clothesline sags down by 3 feet. What is
    13·2 answers
  • How does the current values in and out of the battery compare to the sum of currents going through the light bulbs?
    11·1 answer
  • Write a five paragraph essay discussing the creation of the National Aeronautics and Space Administration, NASA. Compare it to o
    7·1 answer
  • Suppose that an electromagnetic wave is traveling toward the east. At one instant at a given point, the electric field vector po
    11·1 answer
  • how does the graph of displacement versus time look for something moving at a constant positive velocity
    8·1 answer
  • Light travels at a speed of 186,000 miles a second. The distance light travels in a year is:
    8·2 answers
  • A track coach measures the 100-meter time of a track athlete. The runner completes the distance in 11.5 seconds. If the stopwatc
    8·2 answers
  • Part C
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!