A pump jack scaffold must be fitted with two positive gripping mechanisms to prevent slippage. Pump jacks are a uniquely designed scaffold consisting of a platform supported by movable brackets on vertical poles. The brackets are designed to be raised and lowered in a manner similar to an automobile jack. It is important to make sure that pump jack brackets have two positive gripping mechanisms to prevent any failure or slippage.
Answer:
Friction is a force that holds back the movement of a sliding object.
Explanation:
The two types of friction: Static friction and Kinetic friction. Static friction operates between two surfaces that aren't moving relative to each other, while kinetic friction acts between objects in motion.
Answer:
The change in current at
is 
Explanation:
From the question we are told that
The resistance is 
The current is 
The change in voltage with respect to time is 
The change in resistance with time is 
According to ohm's law

differentiating with respect to time using chain rule

substituting value at R = 456

