Jumping with a parachute is feeling free from everything; it is to be very close to God on high; it's a unique feeling; incredible and indescribable feeling; it's a unique emotion. All these statements are made by people who jump with a parachute and to all sportsmen in love with this sport there is a message: thank the air resistance force, as it is the one who prevents your practically free fall due to the contact with the canvas of the parachute. Understand what air resistance force is:
The resistance force of the air gives immense emotions to some athletes.
When a body moves in contact with a liquid or gas, these means apply forces that oppose the movement.
For bodies moving in air, the drag force that the air will apply to them is given by: Fr = k.v2.
Fr = air resistance force (N).
k = constant that depends on the shape of the body and the cross-sectional area of the body, which is perpendicular to the direction of movement (N.s²/m²).
v = speed (m/s)
When jumping from a parachute, the following situations occur:
1. Jump with the parachute closed and the athlete's body horizontally.
Fre = ke.v² logo Fre - P = m.a
2. After the jump, the parachute will open.
Frp = kp.v² logo Frp – P = m.a
The cross-sectional area of the parachute is greater than that of the athlete, which makes kp > ke and therefore Frp > Fre.
So we see that the drag force of the air in situation two is greater than in situation 1, and the limit speed that the athlete will reach after the parachute is opened is given when Frp = P.
From the previous expression we take that:
kpv² = P
v2 = P/k
v = [√ P/k)] – limit speed or maximum speed.
Do not stop now... There's more after the advertising ;)
By Frederico Borges de Almeida
Graduated in Physics
Brazil School Team
mechanics - Physics - Brazil School
Would you like to reference this text in a school or academic work? Look:
ALMEIDA, Frederico Borges de. "Air Resistance Force"; Brazil School. Available in: https://brasilescola.uol.com.br/fisica/forca-resistencia-ar.htm. Accessed on June 27, 2021.
