Answer:
The net upward force the man experiences is approximately 1,324.8 N
The net downward force the man experienced is approximately 556.8 N
Explanation:
The given mass of the man, m = 96 kg
The acceleration of the elevator, a = 4.0 m/s²
According to Newton's third law of motion which states that action ad reaction are equal and opposite, when the elevator moves upwards, we have;
The net force the man experiences, F = Gravitational force, m·g + The force of the elevator pushing upwards, m·a
∴ ↑F = m·g + m·a
Where;
F = The net force the man experiences
m = The mass of the man = 96 kg
g = The acceleration due to gravity ≈ 9.8 m/s²
a = The acceleration of the elevator = 4 m/s²
∴ ↑F = 96 kg × 9.8 m/s² + 96 kg × 4 m/s² ≈ 1,324.8 N
The net upward force the man experiences ≈ 1,324.8 N
When the elevator moves downwards, we have;
The net force the man experiences, F = Gravitational force, m·g + The loss of the gravitational force as the floor moves further downwards, -(m·a)
∴ F = m·g + -(m·a) = m·g - m·a
F = m·g - m·a
∴ ↓F = 96 kg × 9.8 m/s² - 96 k × 4 m/s² ≈ 556.8 N
The net downward force the man experienced ≈ 556.8 N
