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2 years ago

5

hai điện tích điểm bằng nhau có độ lớn 6.10^-8C đặt cách nhau một khoảng là r trong dầu hỏa có hằng số điện môi E=2,1. Lực tương

tác tĩnh điện giữa chúng laf3,85.10^-4. tìm r

1 answer:

nadezda [96]2 years ago

5 0

Answer:

hai điện tích điểm bằng nhau có độ lớn 6.10^-8C đặt cách nhau một khoảng là r trong dầu hỏa có hằng số điện môi E=2,1. Lực tương tác tĩnh điện giữa chúng laf3,85.10^-4. tìm r

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At what displacement of a sho is the energy half kinetic and half potential? what fraction of the total energy of a sho is kinet

expeople1 [14]

As we know that KE and PE is same at a given position

so we will have as a function of position given as

$KE = \frac{1}{2}m\omega^2(A^2 - x^2)$

also the PE is given as function of position as

$PE = \frac{1}{2}m\omega^2x^2$

now it is given that

KE = PE

now we will have

$\frac{1}{2}m\omega^2(A^2 - x^2) = \frac{1}{2}m\omega^2x^2$

$A^2 - x^2 = x^2$

$2x^2 = A^2$

$x = \frac{A}{\sqrt2}$

so the position is 0.707 times of amplitude when KE and PE will be same

Part b)

KE of SHO at x = A/3

we can use the formula

$KE = \frac{1}{2}m\omega^2(A^2 - x^2)$

now to find the fraction of kinetic energy

$f = \frac{KE}{TE} = \frac{A^2 - x^2}{A^2}$

$f = \frac{A^2 - (\frac{A}{3})^2}{A^2}$

$f_k = \frac{8}{9}$

now since total energy is sum of KE and PE

so fraction of PE at the same position will be

$f_{PE} = 1 - f_k$

$f_{PE} = 1 - (8/9) = 1/9$

7 0

3 years ago

A large crane consists of a 20 m, 3,000 kg arm that extends horizontally on top of a vertical tower. The arm extends 15 m toward

Anni [7]

Answer:

$m=18000kg$

Explanation:

From the question we are told that:

Crane Length $l=20m$

Crane Mass $m_a=3000kg$

Arm extension at lifting end $l_l=15m$

Arm extension at counter weight end $l_c=5m$

Load $M_l=5000kg$

Generally the equation for Torque Balance is mathematically given by

$T_1 *l_c-(m_a*g) *l_c-(T_2)*l_l=0$

$mg*5 *-(3000*9.8) *5-(5000*9.8)*15=0$

$m=18000kg$

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3 years ago

If a machine increases force it must apply the force over a long distance? True or false

Eduardwww [97]

Answer: The machine must apply the force over a shorter distance. That's because a machine doesn't change the amount of work and work equals force times distance. Therefore, if force increases, distance must decrease

FALSE

HOPE THIS HELPS

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2 years ago

A person walks 2 miles every day to work, leaving her front porch at 7:00 A.M. and arriving at work at 7:30 A.M. ON the way home

Nataly [62]

Answer:

The displacement is zero miles

Explanation:

The displacement of an object that moves from point A to point B is defined as

$d =B-A$

Where d is the displacement of the object. The displacement does not depend on the trajectory of the object. It only depends on the linear distance between the end point and the starting point.

In this case we know that the person walks from home to work and then walks from work to home. Therefore, the total displacement is the linear distance between the point where its journey begins and the point where the route ends.

The tour begins on the front porch of your house and ends on the front porch of your house (when you return from work). If we call A to the front porch of the house then the displacement is:

$d = A-A = 0$

The displacement is zero miles, since the person finishes the journey just where it started (front porch)

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3 years ago

Name some devices we use to make measurements

NikAS [45]

Answer:

Explanation:

Ruler. A steel ruler aids the measurement and layout of straight lines. The ruler, also called "straightedge" or "straight-edged ruler," is a long, thin strip of wood, metal or plastic marked with increments of measurement.

Measuring Tape. The modern measuring tape's roughly palm-sized casing contains a coiled strip of metal marked with increments of measurement. The metal strip, called "tape," attaches to a spring which automatically retracts the tape into the casing following use.

Walking Tape Measure. The walking tape measure, also called "surveyor's measure," records the distance traveled by a wheel. An operator pushes the measure's wheel, similar to a bicycle wheel, by a handle as an attached ticker box displays feet or meters in the same format as a car's odometer.

Laser Measure. The laser measure offers point and shoot distance measurement. In its most basic form, a laser measure is a hand-held electronic device with a digital display.

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2 years ago