Answer:
a) dynamic equilibrium; b) No equilibrium; c) Static equilibrium; d) Dynamic equilibrium; e) Not equilibrium; f) Dynamic equilibrium.
Explanation:
a) In this case, the girder is in dynamic equilibrium, although there is movement it is realized at constant speed therefore there is no acceleration and the sum of forces is equal to zero.
b) There is no equilibrium since the velocity is decreasing it slows the girder, therefore the sum of forces will be equal to the product of mass by acceleration according to newton's second law.
c) In this case, the arms of the person are exercising each 100 lb, in order to keep the barbell stable, this allows the static equilibrium.
d) There is movement but however the jet will move at constant speed without any kind of acceleration, therefore it has a condition of dynamic equilibrium.
e) There is no balance as the rock falls and the acceleration due to gravity causes its speed to increase as it goes down.
f) In this case there is dynamic equilibrium as there was a deceleration movement however this force value given by the deceleration multiplied by the mass is not large enough to be able to move the box, due to the weight of the box plus the friction force between the box and the surface.
Speed = distance/time
= 400/72
=5.55 m/s
First, let us derive our working equation. We all know that pressure is the force exerted on an area of space. In equation, that would be: P = F/A. From Newton's Law of Second Motion, force is equal to the product of mass and gravity: F = mg. So, we can substitute F to the first equation so that it becomes, P = mg/A. Now, pressure can also be determined as the force exerted by a fluid on an area. This fluid can be measure in terms of volume. Relating volume and mass, we use the parameter of density: ρ = m/V. Simplifying further in terms of height, Volume is the product of the cross-sectional area and the height. So, V = A*h. The working equation will then be derived to be:
P = ρgh
This type of pressure is called the hydrostatic pressure, the pressure exerted by the fluid over a known height. Next, we find the literature data of the density of seawater. From studies, seawater has a density ranging from 1,020 to 1,030 kg/m³. Let's just use 1,020 kg/m³. Substituting the values and making sure that the units are consistent:
P = (1,020 kg/m³)(9.81 m/s²)(11 km)*(1,000 m/1km)
P = 110,068,200 Pa or 110.07 MPa
