Respuesta :
Answer:
F = 518.4 KN
Explanation:
From work energy theorem;
Energy = workdone
In this case, Energy is kinetic energy and has a formula ½mv²
Thus;
Fd = ½mv²
We are given;
Mass of car; m = 1600 kg
Speed of car after crash; v = 18 m/s
Distance from dummy to steering wheel; d = 0.5 m
Thus;
½ × 1600 × 18² = F × 0.5
This gives;
800 × 324 = 0.5F
F = 800 × 324/0.5
F = 518400 N
F = 518.4 KN
Answer: A -9.35
Explanation: The work-energy theorem states the work (Fd) is equal to the change in kinetic energy: Fd = ΔKE. Before the crash, the kinetic energy of the dummy is equal to one-half mass times velocity squared, or 0.5 · 75 kg · (18 m/s)2, which is equal to 12,150 J. The kinetic energy of the dummy after the crash is 0 J, so the change in kinetic energy is –12,150 J. If the crumple zone collapses completely and the dummy just misses hitting the steering wheel, then the distance d is 0.80 + 0.50 = 1.30 m. So we have:
F · d = ΔKE
F = ΔKE/d
F = –12,150 J/1.30 m = 9,346 N, or 9.35 kN
