# Micheale Morgan

### Physics help please - mastering physics?

I'm completely lost have no clue where to start or anything.

Problem 5.63

A 2.50 box that is several hundred meters above the surface of the earth is suspended from the end of a short vertical rope of negligible mass. A time-dependent upward force is applied to the upper end of the rope, and this results in a tension in the rope of . The box is at rest at . The only forces on the box are the tension in the rope and gravity.

What is the velocity of the box at 1.00 ?

What is the velocity of the box at 3.00 ?

What is the maximum distance that the box descends below its initial position?

At what value of does the box return to its initial position?

1 AnswerPhysics8 years ago### Calc Help Let u = e^(a^2 k^2 t) sin(kx)?

Let u = e^(a^2 k^2 t) sin(kx). Verify that u subscript (t) = a^2u subscript (xx)

1 AnswerMathematics8 years ago### A primitive roller coaster track follows a straight line before entering a circular turn. The position of the?

A primitive roller coaster track follows a straight line before entering a

circular turn. The position of the car is given by the following prame-

terization.

r(t) =

(1i + t j + 0 k; t < 0

cos(t) I + sin(t) J + 0 k; t >= 0

(a) Find the velocity vector as a function of time. Your answer will

be a piecewise function.

(b) Verify that the car moves with a constant speed.

(c) Find the acceleration vector as a function of time. Your answer

will be a piecewise function.

(d) Find lim as t->0- a(t)

and lim as t->0+ a(t)

(e) Based on part (d), describe what it would feel like to ride this

roller coaster at time 0.

1 AnswerPhysics8 years ago### Show that if u + v and u - v are orthogonal then u and v have the same length.?

Remember ||w||^2 = w dot w

Engineering8 years ago### The Bernoulli spiral has a parameterization r(t) = e^t cos(4t)i + e^ sin(4t)j?

The Bernoulli spira has a parameterization

r(t) = e^t cos(4t)i + e^t sin(4t)j :

(a) Verify that the angle between r(t) and r'(t) is constant.

(b) Find that angle in degrees.

3 AnswersMathematics8 years ago### Suppose that y = f(x) is a dierntiable function. Let r(t) =ti+f(t)j?

Suppose that y = f(x) is a dierentiable function. Let r(t) = ti +f(t)j .

(a) Compute the velocity vector r'(t) in terms of f and t.

(b) What is the relationship between r'(t) and f'(t)? Explain in one

or two sentences.

(c) Compute the speed |r'(t)| in terms of f and t.

(d) For which functions will the speed of r be constant?

1 AnswerMathematics8 years ago### Show that if u + v and u - v are orthogonal then u and v have the same length.?

u and v are vectors

1 AnswerEngineering8 years ago### Determine whether the following parameterized curves collide or inter- sect (or neither)?

Determine whether the following parameterized curves collide or inter-

sect (or neither).

r1(t) = ti + t^2j + t3 k

r2(t) = (4t + 6)i + 4t^2j + (7 - t) k

1 AnswerPhysics8 years ago### True or flase 3D lines and planes questions?

1. Two lines parallel to a third line are parallel

2. A plane and a line either intersect or are parallel

3. Two planes orthogonal to a third plane are parallel

4. Two planes either intersect or are parallel

5. Two lines orthogonal to a third line are parallel

6. Two lines orthogonal to a plane are parallel

7. Two planes parallel to a line are parallel

8. Two lines parallel to a plane are parallel

9. Two lines either intersect or are parallel

10. Two planes parallel to a third plane are parallel

11. Two planes orthogonal to a line are parallel

1 AnswerEngineering8 years ago### Sketch the triangle with vertices O,(0,0,0) P,(0,5,5) and Q,(4,0,7) and compute its area using cross products.?

I keep getting area=45 but it tells me it is wrong?

1 AnswerEngineering8 years ago### Find the displacement.?

A helicopter begins at point (1,0,1) it flies for 2 km in a direction parallel to the y axis. It then turns 45 degrees right and flies an additional 1 km and the moves vertically upwards 200m.

1 AnswerPhysics8 years ago### Use dot product properties to verify that for vectors v and w of the same size ||v+w||^2-||v-w||^2=4(v dot w)?

Do not use components

1 AnswerEngineering8 years ago### Find the two unit vecotrs in the xy plane that are prallel to the tangent line of the parabola y=2x^2.....?

Find the tow unit vecotrs in the xy plane that are prallel to the tangent line of the parabola y=2x^2 at the point (2,8). Then find the unit vectors on the plane that are perpendicular to the tangent line of that curve at that point.

This is calc 3 homework, if you don't want to tell me the answer at least tell me the steps to find it. All help is greatly appreciated.

1 AnswerMathematics8 years ago### Convert the vector F=(-10+5j) from rectangular to polar form?

i and j are unit vectors, where i = (1angle0) and j = (1angle90) that is find the magnitude of F and the angle of F in degrees.

Please show all steps I don't even know where to begin.

4 AnswersEngineering9 years ago### Best entry level Digital SLR?

I'm looking to buy a D SLR soon, and need a little help. I originally wanted a Nikon D3000 but upon looking I am trying to find something a little cheaper since I'm really low on money. I'm not against buying a refurbished model. Any suggestions are welcome. I'm currently interested in a refurbished sony alpha a230, http://store.sony.com/webapp/wcs/stores/servlet/Pr... . Comments on this model or something else that I should consider?

3 AnswersCameras9 years ago### Sony Vaio message: A desk read error occurred, Press Ctrl+Alt+Del to restart.?

I don't have any extrenal drives plugged in or cd's in the drive. When it restarts I get the same message over and over.

When the Vaio log comes up I pressed F10 to try and go into factory restore mode but it wont load, it goes to starting Windows screen and then I get a black screen with a mouse.

I'm in college so I really need this fixed fast. I tried all I know. Any suggestions appreciated.

1 AnswerLaptops & Notebooks9 years ago### The power delievered by a battery to an apparatus of resistance R (in ohms) is P = 2.25R/(R + 0.5)^2 watts.?

find the rate of change of power with respect to resistance for R = 3 and R = 5

3 AnswersEngineering9 years ago### Find the velocity of an object dropped from a height of 300m at the moment it hits the ground?

s(t) = Snot-Vnot(t)+.5gt^2

how many seconds till it hits the ground and i can figure out the velocity

5 AnswersPhysics9 years ago