What do you need to calculate the mechanical advantage of a block and tackle? a. resistance force
b. effort force
c. number of rope segments that support the resistance weight
d. number of pulleys in the block and tackle system

At 20∘c, the hole in an aluminum ring is 2.800 cm in diameter. you need to slip this ring over a steel shaft that has a room-temperature diameter of 2.804 cm . 1. to what common temperature should the ring and the shaft be heated so that the ring will just fit onto the shaft? coefficients of linear thermal expansion of steel and aluminum are 12×10−6 k−1 and23×10−6 k−1 respectively.