What is the upward force acting on a skydiver of mass 60 kg who is falling at a uniform speed of 2 m/s?
- A.0
- B.60 N
- C.588 N
- D.708 N
Correct answer
Explanation
The correct answer is C, 588 N. At uniform speed the net force is zero, so the upward force must equal the skydiver's weight.
Weight is mass times the acceleration due to gravity: 60 kg × 9.8 m/s² = 588 N, acting downward. Because the skydiver is not speeding up or slowing down, Newton's first law says the forces are balanced. The upward force, mainly air resistance on the body and parachute, is therefore also 588 N. This steady speed is called terminal velocity. The value of the speed, 2 m/s, does not enter the calculation at all.
A is wrong because a zero upward force would leave gravity unbalanced and the skydiver would keep accelerating.
B is wrong because 60 N confuses the mass in kilograms with a force in newtons.
D is wrong because 708 N is more than the weight and would slow the skydiver down instead of keeping the speed steady.
Exam tip: constant velocity means zero net force, so drag equals weight, mg.
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