5. (serway 9th ed., 7-3) in 1990, walter arfeuille of belgium lifted a 281.5-kg object through a distance of 17.1 cm using only his teeth. (a) how much work was done on the object by arfeuille in this lift, assuming the object was lifted at constant speed? (b) what total force was exerted on arfeuille’s teeth during the lift? (ans. (a) 472 j; (b) 2.76 kn)

The crank oa rotates in the vertical plane with a constant clockwise angular velocity ω0 of 5.6 rad/s. for the position where oa is horizontal, calculate the force under the light roller b of the 10.6-kg slender bar ab.

During the experiment if you could triple the breakaway magnetic force with all other quantities left unchanged, what is the new value for the critical velocity if it was v0 (initial velocity), initially? (b) now if you halved the radius with all other quantities left unchanged, what is the new critical velocity if it was v0 (initial velocity), initially? (c) if during the experiment, critical velocity quadrupled with all other quantities left unchanged, what is the new breakaway force if its magnitude was initially f0,?

Aforce of 100 newtons is used to move an object a distance of 15 meters with a power of 50 watts. find the work dine and the time it takes to do the work