## Precalculus (6th Edition) Blitzer

a) The magnitude of the force is $\text{273 lb}$. b) The magnitude of the force is $\text{61 lb}$.
(a) For calculating the magnitude of the force, the law of cosines is applied as the barrel makes the angle with the ramp along horizontal direction, so we will take into account only horizontal component. Therefore we get $280\cos 12.5{}^\circ =273\text{ lb}$ (b) The magnitude of the barrel against the ramp is calculated by using the law of sine’s because in this case we take only vertical component into account and ignore the horizontal components. Therefore, we get $280\sin 12.5{}^\circ =61\text{ lb}$