Answer:9.75 m/s
Explanation:
Given
Length of ladder 
Foot the ladder is moving away with speed of 
From diagram
------1
at 


Now differentiating equation 1 w.r.t time




negative indicates distance is decreasing with time
Answer:
2271.16N/C upward
Explanation:
The diagram well illustrate all the forces acting on the mass. The weight is acting downward and the force is acting upward in other to balance the weight.since the question says it is motionless, then indeed the forces are balanced.
First we determine the downward weight using

Hence for a mass of 3.82g 0r 0.00382kg we have the weight to be


To calculate the electric field,

Since the charge on the mass is negative, in order to generate upward force, there must be a like charge below it that is repelling it, Hebce we can conclude that the electric field lines are upward.
Hence the magnitude of the electric force is 2271.16N/C and the direction is upward
If your machine has a mechanical advantage of 2.5, then WHATEVER force you apply to the input, the force at the output will be 2.5 times as great.
If you apply 1 newton to the machine's input, the output force is
(2.5 x 1 newton) = 2.5 newtons.
If you apply 120 newtons to the machine's input, the output force is
(2.5 x 120 newtons) = 300 newtons.
No it won't. It'll vary inversely as the square of the separation.