Answer:
We show added energy to a system as +Q or -W
Explanation:
The first law of thermodynamics states that, in an isolated system, energy can neither be created nor be destroyed;
Energy is added to the internal energy of a system as either work energy or heat energy as follows;
ΔU = Q - W
Therefore, when energy is added as heat energy to a system, we show the energy as positive Q (+Q), when energy is added to the system in the form of work, we show the energy as minus W (-W).
Answer:
123.48J
Explanation:
Given parameters:
Mass of the ball = 2.8kg
Height = 4.5m
Unknown:
Potential energy = ?
Solution:
The potential energy is the energy due to the position of a body. It is mathematically given as;
P.E = mgh
m is the mass
g is the acceleration due to gravity
h is the height
Now insert the parameters and solve;
P.E = 2.8 x 4.5 x 9.8 = 123.48J
