Physics work problem -- mastering physics 1. The problem statement, all variables and given/known data Find the work W done by the 15-newton force. 2. Relevant equations W=\vec F\cdot\vec s=\left|\vec F\right|\left|\vec s\right|\cos \theta 3. The attempt at a solution W= 15*cos140*160 = -1838.506 I don't know why mastering physics was telling me "Not quite. Check through your calculations; you may have made a rounding error or used the wrong number of significant figures."