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3 years ago

B. Explain why it is more difficult to move an object at rest, than to keep an object moving

Physics

1 answer:

Y_Kistochka [10]3 years ago

5 0

Answer:

The reason is that the value of static friction between two contact surfaces is always greater than that of the kinetic friction between the same surfaces.

Explanation:

When a body is at rest on another body, the two surfaces exert a force called static friction that prevents the surfaces from sliding.

When one of the body is in motion, the two contact surfaces exert a force between them in the direction opposite to the direction of motion is called kinetic friction. It opposes the motion of the body.

The kinetic friction acts on the surfaces only when there is a motion associated with the surface with respect to the other.

The equation for static and kinetic friction is

F = μₓ · η

Both static and kinetic forces have the same dimension. Only they differ is in the value of the coefficient of friction.

On analyzing the friction between two surfaces, the static friction of the two contact surfaces is always greater than that of their kinetic friction.

Hence, it is more difficult to move an object at rest, than to keep an object moving with uniform motion.

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Jane has a mass of 55 kg and his body covers 700 nails with a surface area of 1.00 mm,

Oksana_A [137]

We have,

Jane mass is 55 kg
His body covered with 700 nails all of them having a surface area of 1.00 mm² each = 700 × 1 = 700 mm² = 700/1000000 = 7/10000

We know that,

Pressure = Force/Area

Let's calculate force as we already have area;

F = ma
F = 55 × 9.8 { Acceleration due to gravity }
F = 539 N

Now, if should she would be on 700 nails then pressure will be;

P = F/A
P = 539/7 × 10000
P = 5390000/7
P = 770,000 Pascal

And if should would be on a 1 nail only,

P = F/A
P = 539/1 × 1000000
P = 539000000 Pascal

As, you can notice yourself that the pressure will be so high with only 1 nail and because of this, nail will pass through jane's body.

6 0

3 years ago

On the moon, the acceleration due to gravity is one-sixth that of earth. That is gmoon = gearth /6 = (9.8 m/s2 )/6 = 1.63 m/s2 .

MAVERICK [17]

The pendulum would differ from 300 inches

8 0

3 years ago

A physicist's right eye is presbyopic (i.e., farsighted). This eye can see clearly only beyond a distance of 97 cm, which makes

Ivan

Answer:

f = 19,877 cm and P = 5D

Explanation:

This is a lens focal length exercise, which must be solved with the optical constructor equation

1 / f = 1 / p + 1 / q

where f is the focal length, p is the distance to the object and q is the distance to the image.

In this case the object is placed p = 25 cm from the eye, to be able to see it clearly the image must be at q = 97 cm from the eye

let's calculate

1 / f = 1/97 + 1/25

1 / f = 0.05

f = 19,877 cm

the power of a lens is defined by the inverse of the focal length in meters

P = 1 / f

P = 1 / 19,877 10-2

P = 5D

5 0

3 years ago

You drive your car 3 hrs at an average of 130 km how far did you go

Bingel [31]

You have traveled 390 km. In order to find your answer all you have to do is multiply your speed which is 130 km/h by 3 hrs. That's my friend is how you get your answer! Have a great day!

7 0

4 years ago

Three forces act on an object. Two of the forces are at an angle of 100◦to each other and have magnitude 25N and 12N. The third

seraphim [82]

Answer:

F₄ = 29.819 N

Explanation:

Given

F₁ = (- 25*Cos 50° i + 25*Sin 50° j + 0 k) N

F₂ = (12*Cos 50° i + 12*Sin 50° j + 0 k) N

F₃ = (0 i + 0 j + 4 k) N

Then we have

F₁ + F₂ + F₃ + F₄ = 0

⇒ F₄ = - (F₁ + F₂ + F₃)

⇒ F₄ = - ((- 25*Cos 50° i + 25*Sin 50° j) N + (12*Cos 50° i + 12*Sin 50° j) N + (4 k) N) = (13*Cos 50° i - 37*Sin 50° j - 4 k) N

The magnitude of the force will be

F₄ = √((13*Cos 50°)² + (- 37*Sin 50°)² + (- 4)²) N = 29.819 N

6 0

3 years ago