Question

A parachute is designed to increase the amount of air resistance (which is a form of friction)
experienced by a falling person.

If a 55 kg person is falling on Earth, how much frictional force must the parachute provide in order to
have the person undergo a net acceleration of 0 m/s^2?

answers:
55 N

392 N

657 N

540 N

Answer 1

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**.