Answer:
a) F = - 1.21 10⁶ N, b) F = - 8.06 10⁴ N
Explanation:
a) For this part let's use the kinematics relations
v² = v₀² - 2 a x
distance traveled to stop is x = 1.00 cm = 0.0100 cm, final speed is zero
0 = v₀² - 2 ax
a = v₀² / 2x
a = [tex]\frac{19^2 }{2 \ 0.01}[/tex]
a = 1.81 10⁴ m / s²
this acceleration is in the opposite direction to velocity
let's use Newton's second law
F = ma
F = 67.0 (-1.81 10⁴)
F = - 1.21 10⁶ N
the negative sign indicates that it is going in the opposite direction to the speed
b) in this case it is stopped by an airbag x = 15.0 cm = 0.15 m
a = v₀² / 2x
a = [tex]\frac{19^2}{2 \ 0.15}[/tex]
a = 1.203 10³ m / s²
calculate the force
F = m a
F = 67.0 (- 1.203 10³)
F = - 8.06 10⁴ N