1. calculate the work done in raising 120 lb to a height of 15.0 ft. find the work done in raising 250 g a distance of 215 cm.
2. a screw jack has a handle of radius 36 in and thread pitch of .25in. calculate the ima of the jack
me

1. 1800 lb ft, 5.27 J

2. 905

Explanation:

1. Work is the change in energy.

W = mgh

W = (120 lb) (15 ft)

W = 1800 lb ft

W = mgh

W = (0.250 kg) (9.8 m/s²) (2.15 m)

W = 5.27 J

2. The IMA (ideal mechanical advantage) of a screw is the circumference of the screw divided by the pitch.

IMA = 2πr / p

The IMA of a handle (lever) is the circumference of the handle divided by the circumference of the screw.

IMA = 2πR / 2πr

The total IMA is the product:

IMA = (2πR / 2πr) (2πr / p)

IMA = 2πR / p

IMA = 2π (36) / (0.25)

IMA = 905

answer( sicar );