Question

Парашютист массой 70 кг опускается с раскрытым парашютом . Какова сила сопротивления воздуха при равномерном движении? Чему равна при этом равнодействующая приложенных к парашютисту сил? Чему равен вес парашютисту?

Answer 1

Fт - Fсопр. = ma ; a = 0; - равнодействующая = 0, т.к движение равномерное;

Fт. = Fсопр. ; Fт. = mg = 70*10 = 700Н

Fсопр. = 700H

P = Fт. = 700Н - вес равен силе тяги.

 

Answer 2

Parachutist's Weight and Air Resistance

When a parachutist with a mass of 70 kg descends with an open parachute, there are two forces acting on them: the force of gravity and the force of air resistance.

The weight of the parachutist is equal to the force of gravity acting on them. The weight can be calculated using the formula:

Weight = mass x acceleration due to gravity

In this case, the mass of the parachutist is 70 kg. The acceleration due to gravity is approximately 9.8 m/s^2. Therefore, the weight of the parachutist is:

Weight = 70 kg x 9.8 m/s^2 = 686 N.

The force of air resistance is the opposing force that acts against the motion of the parachutist. It depends on various factors such as the size and shape of the parachute, the speed of descent, and the density of the air.

Unfortunately, the specific value for the force of air resistance in this scenario is not provided in the search results. However, we can assume that the force of air resistance will be significant enough to slow down the descent of the parachutist and provide a safe landing.

Resultant Force on the Parachutist

The resultant force on the parachutist is the vector sum of the weight and the force of air resistance. It determines the direction and magnitude of the parachutist's motion.

If the parachutist is descending at a constant velocity (uniform motion), the resultant force on them is zero. This means that the force of air resistance is equal in magnitude and opposite in direction to the weight of the parachutist.

Therefore, the resultant force on the parachutist is zero.

Conclusion

In summary, when a parachutist with a mass of 70 kg descends with an open parachute, the force of air resistance opposes the force of gravity (weight). The resultant force on the parachutist is zero when they are descending at a constant velocity. The specific value for the force of air resistance is not provided in the search results, but it is significant enough to slow down the parachutist's descent and ensure a safe landing.

Please note that the information provided is based on the available search results and may not be exhaustive.