Answer:
K = -½U
Explanation:
From Newton's law of gravitation, the formula for gravitational potential energy is;
U = -GMm/R
Where,
G is gravitational constant
M and m are the two masses exerting the forces
R is the distance between the two objects
Now, in the question, we are given that kinetic energy is;
K = GMm/2R
Re-rranging, we have;
K = ½(GMm/R)
Comparing the equation of kinetic energy to that of potential energy, we can derive that gravitational kinetic energy can be expressed in terms of potential energy as;
K = -½U
Answer:

Explanation:
It is given that,
Mass of Albertine, m = 60 kg
It can be assumed, the spring constant of the spring, k = 95 N/m
Compression in the spring, x = 5 m
A glass sits 19.8 m from her outstretched foot, h = 19.8 m
When she just reach the glass without knocking it over, a force of friction will also act on it. Using the conservation of energy for the spring mass system such that,




So, the coefficient of kinetic friction between the chair and the waxed floor is 0.101. Hence, this is the required solution.
Answer:
187 J
Explanation:
First Law of Thermodynamics :
ΔQ = ΔW + ΔU
ΔQ : Heat. If it added to system then positive and if it is rejected by system then negative.
ΔW : Work. If it done by the system then positive and if it is done on system then negative.
ΔU : Internal Energy. If it positive then temperature of system increased and if it is negative then temperature of system decreased.
ΔQ = 79 J
ΔW = - 108 J
ΔU = ?
substituting the value in the equation:
79 = -108 + ΔU
∴ ΔU = 187 J