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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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Answer:

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Explanation:

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The horizontal displacement is going to be the distance travelled, horizontally of course, once the package is released;

First thing to understand is that the vertical and horizontal components are to be dealt with separately because they don't affect each other;

Since there is no horizontal acceleration (ignoring air resistance), we simply require a velocity and time to find the horizontal displacement, using the formula v = d/t (or speed = distance/time);

What we have is the horizontal velocity but we don't have the time taken;

One thing we know is that the time elapsed for the vertical fall of 800m and for the horizontal displacement must be the same;

What we do, therefore, is find the time taken for the vertical displacement using the formula, s = ut + ¹/₂·at², since we know the vertical velocity, height and acceleration:

800 = (0)t + ¹/₂·(9.8)t²

800 = 4.9t²

t² = 163.26...

t = 12.77...

We now have the time taken for the vertical fall and the horizontal displacement, we can use this with the horizontal velocity we know already and get the horizontal displacement:

$u_{h} = \frac{s_{h} }{t} \\\\ 200 = \frac{s_{h} }{12.77...} \\\\ s_{h} = 200(12.77...) \\\\ s_{h} = 2555.5...$

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