To determine the amount of frictional force that the parachute must provide to ensure that the person experiences a net acceleration of 0 m/s², we'll need to first calculate the gravitational force acting on the person.
The gravitational force (weight) can be calculated using the formula: \[ F_g = m \cdot g \] where:
- \( m \) is the mass (55 kg in this case),
- \( g \) is the acceleration due to gravity (approximately \( 9.81 , \text{m/s}^2 \) on Earth).
Calculating the gravitational force: \[ F_g = 55 , \text{kg} \times 9.81 , \text{m/s}^2 = 539.55 , \text{N} \]
To achieve a net acceleration of 0 m/s², the parachute must exert an upward frictional force equal to the downward gravitational force. Therefore, the parachute must provide approximately:
\[ F_f = F_g \]
So: \[ F_f = 539.55 , \text{N} \]
Rounding this to an appropriate number of significant figures gives us 540 N. Thus, the answer is:
540 N.