Answer:
(a)ΔEp = 661500 J
(b)ΔEp = -771750 J
Explanation:
Conceptual analysis
We define the potential energy as that which the bodies possess by the fact of being in a certain position.That is, the body has an energy (ability to produce a job) by the fact of being at a certain height above the ground.
The formula for calculating potential energy is as follows:
Ep = m*g*h Formula (1)
Where:
Ep: It is the potential energy of the body in Joules. (J)
m: Body mass. (kg)
g: acceleration due to gravity. (m / s²)
h:height at which the body is. (m)
Change in gravitational potential energy
We define the Change in gravitational potential energy as follows :
ΔEp= Epf- Epi Formula (2)=
Where:
ΔEp: Change in gravitational potential energy (J)
Epf : final potential energy (J)
Epi : initial potential energy (J)
(a) Change in gravitational potential energy on the first day
We apply the formula (1)
hf: final hight = 2400 m
hf: initial hight = 1500 m
We apply the formula (2):
ΔEp= Epf- Epi
We apply the formula (1):
Epf = m*g*hf
Epi = m*g*hi
ΔEp= m*g*hf - m*g*hi :We factor mg
ΔEp= m*g*(hf - *hi ) Equation (1)
ΔEp = 75*98*(2400-1500)
ΔEp =75*9.8(900)
ΔEp = 661500 J
(a) Change in gravitational potential energy on the second day
hi = 2400 m
hf = 1350 m
We apply the equation (1)
ΔEp= m*g*(hf-hi)
ΔEp = 75*9.8*(1350-2400)
ΔEp = 75*9.8*( -1050)
ΔEp = -771750 J