All categories

3 years ago

A man pulls on his dog's leash to keep him from running after a bicycle. Which term best describes this example?

2 answers:

8 0

We know the answer doesn't have to do with force because we have not identified a positive or negative axis.

Depending on what the system we are evaluating is, the sign of the work can change.

If work is done on the system, it is negative, but if work is done by the system, it is positive.

If the system we are evaluating is the leash, the work is being done by the leash, and therefore, the work is positive.

If the system we are evaluating is the dog, the work is being done on the dog, and therefore, the work is negative.

olchik [2.2K]3 years ago

7 0

Answer: so it’s negative work

Explanation:

You might be interested in

1) On the way to the moon, the Apollo astro-

kramer

(1) You must find the point of equilibrium between the two forces,

G * MTms / (R−x)^2 = G * MLms / x^2
MT / (R-x)^2 = ML / x^2

So,

x = R * sqrt(ML * MT) - ML / (MT - ML)
R = is the distance between Earth and Moon.

The result should be,
x = 3.83 * 10^7m
from the center of the Moon, and

R - x = 3.46*10^8 m
from the center of the Earth.

(2) As the distance from the center of the Earth is the number we found before,
d = R - x = 3.46*10^8m
The acceleration at this point is
g = G * MT / d^2
g = 3.33*10^-3 m/s^2

6 0

3 years ago

Give an example of a situation in which you would describe an

Viktor [21]

It would be A because it would make sense

5 0

3 years ago

Why do the golf ball have dimples?

Igoryamba

Answer:

HELLO! I WILL EXPLAIN WHY GOLF BALLS HAVE DIMPLES.

Explanation:

DIMPLES ON A GOLF BALL CREATE A THIN BOUNDARY LAYER OF AIR THAT CLINGS TO THE BALL'S SURFACE. THIS ALLOWS THE AIR TO FOLLOW THE BALL'S SURFACE A LITTLE FARTHER AROUND THE BACKSIDE OF THE BALL, THEREBY DECREASING THE SIZE OF THE WAKE.

I AM SO SORRY ABOUT THE CAP LOCKS I THINK MY CAP LOCKS BUTTON IS PUSHED, AND IT IS NOT POPPING UP FOR SOME REASON.

ANYWAYS, HAVE A GREAT DAY!!!!!!

4 0

2 years ago

Read 2 more answers

A disk with radius R and uniform positive charge density s lies horizontally on a tabletop. A small plastic sphere with mass M a

Yanka [14]

Answer:

a. F = Qs/2ε₀[1 - z/√(z² + R²)] b. h = (1 - 2mgε₀/Qs)R/√[1 - (1 - 2mgε₀/Qs)²]

Explanation:

a. What is the magnitude of the net upward force on the sphere as a function of the height z above the disk?

The electric field due to a charged disk with surface charge density s and radius R at a distance z above the center of the disk is given by

E = s/2ε₀[1 - z/√(z² + R²)]

So, the net force on the small plastic sphere of mass M and charge Q is

F = QE

F = Qs/2ε₀[1 - z/√(z² + R²)]

b. At what height h does the sphere hover?

The sphere hovers at height z = h when the electric force equals the weight of the sphere.

So, F = mg

Qs/2ε₀[1 - z/√(z² + R²)] = mg

when z = h, we have

Qs/2ε₀[1 - h/√(h² + R²)] = mg

[1 - h/√(h² + R²)] = 2mgε₀/Qs

h/√(h² + R²) = 1 - 2mgε₀/Qs

squaring both sides, we have

[h/√(h² + R²)]² = (1 - 2mgε₀/Qs)²

h²/(h² + R²) = (1 - 2mgε₀/Qs)²

cross-multiplying, we have

h² = (1 - 2mgε₀/Qs)²(h² + R²)

expanding the bracket, we have

h² = (1 - 2mgε₀/Qs)²h² + (1 - 2mgε₀/Qs)²R²

collecting like terms, we have

h² - (1 - 2mgε₀/Qs)²h² = (1 - 2mgε₀/Qs)²R²

Factorizing, we have

[1 - (1 - 2mgε₀/Qs)²]h² = (1 - 2mgε₀/Qs)²R²

So, h² = (1 - 2mgε₀/Qs)²R²/[1 - (1 - 2mgε₀/Qs)²]

taking square-root of both sides, we have

√h² = √[(1 - 2mgε₀/Qs)²R²/[1 - (1 - 2mgε₀/Qs)²]]

h = (1 - 2mgε₀/Qs)R/√[1 - (1 - 2mgε₀/Qs)²]

4 0

3 years ago

After exercise your heart rate is

harina [27]

Your heart rate is higher than normal.

7 0

3 years ago

Read 2 more answers