Answer:
Force on the object is 20 N
Explanation:
As we know that work done to raise the book from initial position to final position is known as potential energy stored in it
So here we know that

here we know that
U = 30 J
s = displacement = 1.5 m
so we have


Answer:
The perimeter of the rectangle is 60 units.
Explanation:
The perimeter of a rectangle is given by the equation P = 2L + 2W. With W = 12 units and L = 18 units, substituting the values in the equation above:
P = 2(18 units) + 2(12 units)
P = 36 units + 24 units
P = 60 units
The vertical velocity is affected by the acceleration of gravity (ignoring the effects of air resistance usually)
To solve this problem it is necessary to apply the concewptos related to Torque, kinetic movement and Newton's second Law.
By definition Newton's second law is described as
F= ma
Where,
m= mass
a = Acceleration
Part A) According to the information (and as can be seen in the attached graph) a sum of forces is carried out in mass B, it is obtained that,


In the case of mass A,


Making summation of Torques in the Pulley we have to



Replacing the values previously found,





Replacing with our values


PART B) Ignoring the moment of inertia the acceleration would be given by



Therefore the error would be,



Jeff uses all of his weight to lift the 600 lbs. C is your answer i do believe