Question

If you lift a seven pound object 54 inches how many joules of energy did you use?

Answer 1

w=f*deltax
f=ma
a=9.8(gravitational acceleration)
(7)(9.8)=68.6n
w=(68.6)(54)=3704.4J

Answer 2

-42.68 J

Step-by-step explanation:

Work done = weight x displacement

weight = 7 pound

= (7 x 4.45) N

= 31.15 N

Displacement = 54 inches

1 inch = 0.0254 m

54 in = 1.37 m

Work done = 31.15 N x 1.37 m x cos 180°

= -42.68 J

Thus, the amount of energy used to lift 7 pound object to 54 inches, 42.68 J of energy is used.