Answer:
a) 100 kJ
b) 90.909 × 10³ N
c) 190.08 kJ
Explanation:
Given:
Initial velocity, v₁ = 50 m/s
Final velocity, v₂ = 0
Mass of the pilot, m = 80 kg
Distance covered in snow, d = 1.1 m
Now,
Work done (W) = change in kinetic energy
or
W =
in substituting the values, we get
W =
or
W = 100000 J = 100 kJ
b) Average force exerted by snow
Now, Force = (change in momentum/time taken)
or
F = ΔM/Δt
now,
ΔM = m(v₁ - v₂)
Δt = distance/ (average speed) = 1.1/[(50 + 0)/2] = 0.044 s
F = 80 × (50-0)/0.044
F = 90.909 × 10³ N
c) Work done by air resistance
W = change in energy by the air resistance
now, the change is energy is as:
from potential energy at the height, H = 370 m to the potential energy acquired just before touching the snow
thus,
W = mgH - (1/2)mv₁²
on substituting the values, we get
W = 80 × 9.8 × 370 - (1/2) × 80 × 50² = 190080 J = 190.08 kJ