Question 5
Newton's Laws and MomentumA man of mass m, experiences a viscous drag, F and an upthrust U as he descends towards the ground at a steady velocity, using a parachute. If the acceleration of free fall is g, which of the following expressions is correct?
- A.FU = mg
- B.U+F−mg=0
- C.U−F=mg
- D.F−U−mg=0
Show the answer and explanation
Answer: B (U+F−mg=0)
Explanation
At steady velocity the net force is zero: the upward forces U and F balance the weight mg, so U + F − mg = 0.