Question

A 49 kg skier skis directly down a frictionless slope angled at 13° to the horizontal. Choose the positive direction of the x axis to be downhill along the slope. A wind force with component Fx acts on the skier. What is Fx if the magnitude of the skier's velocity is (a) constant, (b) increasing at a rate of 1.2 m/s2, and (c) increasing at a rate of 2.4 m/s2. Use g = 9.81 m/s2.

Answer 1

given,

mass of skier = 49 kg

angle made with horizontal = 13°

now,

a) skies velocity is constant

F x = m g sin θ -ma

a = 0

F x = 49 × 9.8 × sin 13°

F x = 108 N

b) a = 1.2 m/s²

F x = m g sin θ -ma

F x =49 × 9.8 × sin 13° - 40 ×1.2

F x = 60 N

c) a = 2.4

F x = m g sin θ -ma

F x =49 × 9.8 × sin 13° - 40 × 2.4

F x = 12 N