Question

8. A student lifts a 10.0 pound ball 7.00 feet in 7.00 seconds.

How many joules of work did the student complete?
a. 7 lb, ft
b. 1.42 lb, ft
C. 70 lb, ft
d. 75 lb Ft
9. Convert problem 8 into SI Units and then calculate work.
a. 94.65 )
b. 90 J
c. 100
d. 8J

Answer 1

(a) W = 70 lb-ft (b) 94.85 J

Step-by-step explanation:

Given that,

A student lifts a 10.0 pound ball 7.00 feet in 7.00 seconds.

(a) We need to find the work done.

Work done = Force × displacement

i.e.

W = 10 × 7

W = 70 lb-ft

(b) We know that,

1 lb-foot = 1.355 J

50 lb-ft = (70 × 1.355) J

= 94.85 J

Hence, this is the required solution.