Mary weighs 519 N and she walks down a flight of stairs to a level 3.4 m below her starting point. What is the change in Mary’s potential energy? Answer in units of J.
-519*3.4
To find the change in Mary's potential energy, we can use the equation:
ΔPE = m * g * h
Where,
ΔPE is the change in potential energy,
m is the mass of Mary,
g is the acceleration due to gravity (approximately 9.8 m/s²),
h is the change in height.
In this case, we are given Mary's weight, which is equal to the force of gravity acting on her:
Weight = m * g
So we can rearrange the equation to solve for the mass:
m = Weight / g
Substituting the given values:
m = 519 N / 9.8 m/s² ≈ 52.96 kg
Now, we can calculate the change in potential energy:
ΔPE = m * g * h
ΔPE = 52.96 kg * 9.8 m/s² * 3.4 m
ΔPE ≈ 1789 J
Therefore, the change in Mary's potential energy is approximately 1789 Joules (J).