In the absence of an external force, a moving object will stop immediately. move

Question

In the absence of an external force, a moving object will stop immediately. move with constant velocity for a while and then slow to a stop. move faster and faster. move with constant velocity. When a parachutist jumps from an airplane, he eventually reaches a constant speed, called the terminal velocity. This means that the effect of gravity has died down. the effect of gravity increases as he becomes closer to the ground. the force of air resistance is equal to zero. the force of air resistance is equal to the weight of the parachutist. A force of 120 N is applied to an object whose mass is 30 kg. The object's acceleration is. 4.0 m/s^2 0.25 m/s^2 2.0 m/s^2 150 m/s^2 A 777 aircraft has a mass of 300,000 kg. At a certain instant during its landing, its speed is 27.0 m/s. If the braking force is 445,000 N, what is the speed of the airplane 10.o s later. 18.1 m/s. 10.0 m/s 14.4 m/s 12.2 m/s

Explanation / Answer

1. 4 moves with constant velocity

f = 0

dp/dt = 0

v = constant

2. 4. The force of air resistance is equal to weight of parachutist

3.

F = ma

120 = 30 a

a = 4 m/s2

4.

F = ma

from equation of motion v = u + at

F = m (v - u)/t

- 445000 = 300,000(v - 27)/10

v = 12.2m/s

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.