Answer:
1200 ft·lb
Step-by-step explanation:
On average, you're lifting the 60-lb cable a distance of 15 ft, so doing 900 ft·lb of work. Lifting the 10-lb calculus book 30 ft requires 300 ft·lb of work.
The total work is 900 ft·lb + 300 ft·lb = 1200 ft·lb.
