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3 years ago

Are the objects described here in static equilibrium, dynamic equilibrium, or not equilibrium at all? Explain.

2 answers:

4 0

Let us examine the given situations one at a time.

Case a. A 200-pound barbell is held over your head.
The barbell is in static equilibrium because it is not moving.
Answer: STATIC EQUILIBRIUM

Case b. A girder is being lifted at a constant speed by a crane.
The girder is moving, but not accelerating. It is in dynamic equilibrium.
Answer: DYNAMIC EQUILIBRIUM

Case c: A jet plane has reached its cruising speed at an altitude.
The plane is moving at cruising speed, but not accelerating. It is in dynamic equilibrium.
Answer: DYNAMIC EQUILIBRIUM

Case d: A box in the back of a truck doesn't slide as the truck stops.
The box does not slide because the frictional force between the box and the floor of the truck balances out the inertial force. The box is in static equilibrium.
Answer: STATIC EQUILIBRIUM

nordsb [41]3 years ago

4 0

Statement a and e are in static equilibrium, b and d are in dynamic equilibrium and c is not at equilibrium at all.

<h3>FURTHER EXPLANATION</h3>

When the net force acting on an object is zero, the object is said to be at equilibrium. The state of equilibrium can be classified into two: static and dynamic.

Static equilibrium is when the net force is zero resulting in the object being at rest or not moving.

Dynamic equilibrium is when the resultant force acting on an object is zero and the object is moving in a uniform motion (i.e. constant or unchanging speed).

A. a 200 pound barbell is held above your head

<em>Since the barbel is "held above your head" and is implied to be at rest since there is no change in its position during the time it is held, then this situation is an example of static equilibrium.</em>

B. A girder is being lifted at a constant speed by a crane

<em>This is dynamic equilibrium because the object is moving "at a constant speed".</em>

C. A girder is being lowered into place. It is slowing down.

<em>This is not equilibrium condition because the objects is neither at rest nor moving at a constant speed. It is "slowing down", so the speed is decreasing.</em>

D. A jet plane has reached its cruising speed and altitude.

<em>The "cruising speed" is the speed that is maintained while the jet plane is traveling because this is considered to be the most efficient speed. Since it is maintained, the jet plane is said to be in constant motion. Therefore, this is dynamic equilibrium.</em>

E. A box in the back of a truck doesn't slide as the truck stops.

<em>This is static equilibrium because the box is stationary or not moving.</em>

<em />

<h3>LEARN MORE</h3>

Balanced Forces brainly.com/question/1675020
Resultant Force brainly.com/question/7041906
Friction brainly.com/question/3401004

Keywords: equilibrium, static equilibrium, dynamic equilibrium

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A 562 N trunk is on frictionless plane inclined at 30.0 degrees from the horizontal. What is the acceleration of the trunk down

Len [333]

Answer: 0m/s²

Explanation:

Since the forces acting along the plane are frictional force(Ff) and moving force(Fm), we will take the sum of the forces along the plane

According newton's law of motion

Summation of forces along the plane = mass × acceleration

Frictional force is always acting upwards the plane since the body will always tends to slide downwards on an inclined plane and the moving acts down the plane

Ff = nR where

n is coefficient of friction = tan(theta)

R is normal reaction = Wcos(theta)

Fm = Wsin(theta)

Substituting in the formula of newton's first law we have;

Fm-Ff = ma

Wsin(theta) - nR = ma

Wsin(theta) - n(Wcos(theta)) = ma... 1

Given

W = 562N, theta = 30°, n = tan30°, m = 56.2kg

Substituting in eqn 1,

562sin30° - tan30°(562cos30°) = 56.2a

281 - 281 = 56.2a

0 = 56.2a

a = 0m/s²

This shows that the trunk is not accelerating

4 0

3 years ago

Consider a neutron star of radius 10 km that spins with a period of 0.8 seconds. Imagine a person is standing at the equator of

Arada [10]

Answer:

a = 616850.28 m/s²

Explanation:

Given that,

The radius of the neutron star, r = 10 Km

= 10,000 m

The time period of the neutron star, T = 0.8 s

The centripetal acceleration is given by the formula,

a = v²/r

The linear velocity is given by the relation,

v = rω

The time taken to complete one complete rotation is given by the relation

T = 2π /ω

Where,

ω = 2π / T

Substituting v and ω into the equation for centripetal acceleration. It becomes

a = 4π²r/T²

Substituting the given values in the above equation

a = 4π² x 10000 / 0.8²

= 616850.28 m/s²

Hence, the centripetal acceleration of this person is, a = 616850.28 m/s²

8 0

3 years ago

Describe the role of a generator in producing electricity.

AlekseyPX

Answer:

Option (A)

Explanation:

In the process of producing electric energy, always a turbine rotates.

The rotation of turbine is due to the falling water in case of hydroelectric power station, due to the heat energy in thermal power station.

As the turbine rotates, the energy of one form is converted into mechanical energy of turbine. Now the generator converts the mechanical energy into electrical energy. It is done by the electromagnetic induction.

When a magnetic flux linked with a coil changes, the induced emf is developed in the coil, this phenomenon is called electromagnetic induction.

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3 years ago

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When making a sound source near a reflective surface, such as making a person at a podium, the sound can reflect off of the surf

Liula [17]

Answer:

1. By removing the reflector or reflecting elements

2. By using absorbing material on the reflecting surfaces.

Explanation:

To solve problems caused by reflecting surfaces, you can remove the reflector or reflecting elements. However, sometimes it is enough to turn/move the reflecting element and change the reflections. Furthermore, using absorbing material on the reflecting surface can help reduce comb filtering as well.

In some cases, it is possible to place the sound source so close to the reflecting surface, that there is no suspension between the direct sound and the reflected sound.

5 0

4 years ago

A force of 5N and a force of 8N act to the same point and are inclined at 45degree to each other. Find the magnitude and directi

Alex_Xolod [135]

Magnitude: 12.1 N.
Direction: 17.0° to the 8 N force.

<h3>Explanation</h3>

Refer to the diagram attached (created with GeoGebra). Consider the 5 N force in two directions: parallel to the 8 N force and normal to the 8 N force.

$\displaystyle F_{\text{1, Parallel}} = F_1 \cdot \cos{45^\textdegree} = \dfrac{5\sqrt{2}}{2}\;\text{N}$ .
$\displaystyle F_{\text{1, Normal}} = F_1 \cdot \sin{45^\textdegree} = \dfrac{5\sqrt{2}}{2}\;\text{N}$ .

The sum of forces on each direction will be the resultant force on that direction:

Resultant force parallel to the 8 N force: $(8 + \dfrac{5\sqrt{2}}{2})\;\text{N}$ .
Resultant force normal to the 8 N force: $\dfrac{5\sqrt{2}}{2}\;\text{N}$ .

Apply the Pythagorean Theorem to find the magnitude of the resultant force.

$\displaystyle \Sigma F = \sqrt{{(8 + \dfrac{5\sqrt{2}}{2})}^2 + {(\dfrac{5\sqrt{2}}{2})}^2} = 12.1\;\text{N}$ (3 sig. fig.).

The size of the angle between the resultant force and the 8 N force can be found from the tangent value of the angle. Tangent of the angle:

$\displaystyle \dfrac{\Sigma F_\text{Normal}}{\Sigma F_\text{Parallel}} = \dfrac{8 + \dfrac{5\sqrt{2}}{2}}{\dfrac{5\sqrt{2}}{2}} \approx 0.306491$ .

Find the size of the angle using inverse tangent:

$\displaystyle \arctan{ \dfrac{\Sigma F_\text{Normal}}{\Sigma F_\text{Parallel}}} = \arctan{0.306491} = 17.0\textdegree$ .

In other words, the resultant force is 17.0° relative to the 8 N force.

4 0

3 years ago