Because of friction
, NOT all potential energy is converted to kinetic energy. (B)
Some of the object's potential energy is converted to heat and lost.
Answer:
c. There is a buoyant force that is proportional to the volume of your body that is below the level of the water.
Explanation:
Buoyancy can be defined as a force which is created by the water displaced by an object.
Simply stated, buoyancy is directly proportional to the amount of water that is being displaced by an object.
Hence, the greater the amount of water an object displaces; the greater is the force of buoyancy pushing the object up.
The buoyancy of an object is given by the formula;
Where;
Fb = buoyant force of a liquid acting on an object.
g = acceleration due to gravity.
p = density of the liquid.
v = volume of the liquid displaced.
h = height of liquid (water) displaced by an object.
A = surface area of the floating object.
The unit of measurement for buoyancy is Newton (N).
In this scenario, you are standing on the bottom of a lake with your torso above water. Thus, there is a buoyant force that is proportional to the volume of your body that is below the level of the water.
Answer:
Explanation:
Given
mass of book(m)=2.1 kg
height up to which book is lifted is (h)2.2 m
height of person 
Potential energy of book relative to ground=mgh

(b)PE w.r.t to person head =mg(h-h0)

work done by person in lifting box 2.2 m w.r.t floor
Word done =Potential Energy of box relative to floor=45.2 J
Answer:
0.375
Explanation:
When the 3rd sphere touches the 1st one, the charge will then be distributed between both of them, then now the 1st sphere has only half of his original charge.
In this moment then
Sphere 1 has a charge = Q/2
Sphere 3 has a charge = Q/2
When the 3rd sphere touches the 2nd sphere again the charge is distributed in a manner that both sphere has the same charge.
How the total charge is
Q = Q/2 + Q = 3/2Q,
When the spheres are separated each one has 3/4Q
Sphere 2 has a charge = 3/4Q
Sphere 3 has a charge = 3/4Q
The electrostatic force that acts on sphere 2 due to sphere 1 is:
F = (kq1q2) / r²
F = (Q/2 * 3Q/4) / r²
F = (Q² * 3) / 8r²
From the question, F = 0.42 = kQ²/r²
Thus, we can say that
F = (0.42 * 3) / 8
F = 0.1575
Thus, the ratio between F/F =
0.1575 / 0.42
Ratio, r = 0.375