Answer:
and 
Explanation:
Given
Represent the height as h, the length as l and the width as w.
From the question:
Volume of a box is calculated as:
This gives:
Substitute 9 for V
Make h the subject:
The surface area is calculated as:
Recall that:
Recall that:
So:
To minimize the surface area, we have to differentiate with respect to w
Set A' to 0
Add 
to both sides
Multiply both sides by 
Make 
the subject
Solve for w
![w = \sqrt[3]{\frac{27}{8}}](https://tex.z-dn.net/?f=w%20%3D%20%5Csqrt%5B3%5D%7B%5Cfrac%7B27%7D%7B8%7D%7D)
Recall that : and
Hence, the dimension that minimizes the surface area is:
and
The two factors used to determine the speed of ac motors are the frequency of the power supply and the number of poles in the motor winding.
Explanation:
The frequency of the power supply and the number of poles of the machine states the synchronous speed.
The poles combined with ac line frequency determines the no-load revolutions per minute of the monitor. So all four-pole motors will run at same speed under no-load conditions, then all six-pole motors will run at the same speed.
The speed of the induction motor depends on stator frequency "s ". By varying the stator voltage and constant supply frequency the speed can be controlled. The two main components of the electric motor are stator and rotor.
Answer:
1. Effect of air pressure
2. air- powered wheel chair
3. Pneumatic valves
Explanation:
1. In any pneumatic device, the mipact of air pressure to produce the moving effect on an heavy object is unexpected.
2. pneumatice demultiplexer when air in comprressed tank is allowed released to cause movement of the chair.
3. In industries, a pneumatic valve operates by force of air when actuated. A signal causes actuation of coil. When coil is energized, compressed high pressure air is allowe to enter in a small cylinder and cause operation of valve
Answer:
Employers must comply with OSHA's regulations to safeguard workers from caught-in or -between dangers, which include, but are not limited to, the following:
• Protect power tools and other equipment with moving parts with guards.
• Support, secure, or otherwise make safe any equipment that has pieces that workers could become entangled in.
· Take precautions to avoid workers being crushed by tipped-over heavy machinery.
• Take precautions to avoid pinning workers between equipment and a solid object.
• Provide workers with protection when trenching and excavating.
• Provide ways to prevent constructions, such as scaffolds, from collapsing.
Explanation:
