Explanation:
Let us assume that forces acting at point B are as follows.
= 0 ...... (1)
= 0
= 0 .......... (2)
Hence, formula for allowable normal stress of cable is as follows.
T = 
= 3925 kip
From equation (1), 
= -3925
= -3925
= 12877.29 kip
From equation (2), -12877.29 (Cos 60) + W = 0
= 0
W = 6438.64 kip
Thus, we can conclude that greatest weight of the crate is 6438.64 kip.
The correct answer of this question is : A) Change alternating current into direct current.
EXPLANATION :
As per the question, we are given vacuum tube. Vacuum tube can be of various types. Normally it contains two electrodes called cathode and anode which are enclosed in an evacuated glass chamber . There are also other types of vacuum tubes which contain extra electrodes like control grid .
The vacuum tube can be used as a rectifier. It means that it can be used as an electronic device which will convert alternating current into direct current. It may be a half wave rectifier or a full wave rectifier. Actually the direct current obtained during the rectification of alternating current is pulsating in nature.
Hence, the correct answer is that a vacuum tube can be used to change alternating current into direct current.
Answer:
D and A
Explanation:
Hint The basic difference between them is that a bar magnet is a permanent magnet whereas an electromagnet is a temporary magnet. An electromagnet is formed when an electric current is passed through wires wound around soft metalcore. An electromagnet loses its magnetism once the current flow is stopped.
