Given that weight of 1 kg is equivalent to the weight of 2.2 lb.
The weight of one kg or 2.2 lbF is 9.8 N
(a)
The weight of 2.2 lbF is 9.8 N
Thus the force of 1.0 lbF is,
[tex]\begin{gathered} 1.0\text{ lbF}=\frac{1.0\text{ lbF}\times9.8\text{ N}}{2.2\text{ lbF}} \\ =4.45\text{ N} \end{gathered}[/tex]Thus the force of the weight of 1.0 lbF is 9.8 N
(b)
If the thrusters are meant to use the value in N but used it in lbF, then the trusters would have used, say, 9.8 lbF in place of 9.8 N.
The force of 9.8 lbF is greater than the force of 9.8 N. Thus the force applied to slow the craft is higher than intended.
Thus they would slow the craft more.
(c)
Yes, the failure is correctly explained by the unit mix-up. As it is explained in part b, the force applied will be higher than intended. Which is exactly the case.
Thus the failure is correctly explained by the mix-up.