Exam 9: Static Equilibrium; Elasticity and Fracture

A 120-kg refrigerator that is 2.0 m tall and 85 cm wide has its center of mass at its geometrical center. You are attempting to slide it along the floor by pushing horizontally on the side of the refrigerator. The coefficient of static friction between the floor and the refrigerator is 0.30 . Depending on where you push, the refrigerator may start to tip over before it starts to slide along the floor. What is the highest distance above the floor that you can push the refrigerator so that it will not tip before it begins to slide?

A 1200-kg car is being raised at a constant speed if 25 cm/s by a crane, using a 20-m long steel cable that is 1.5 cm in diameter. Young's modulus for steel is $2.0 \times 10 ^ { 11 } \mathrm {~Pa}$ Iength of the cable caused by the car? What is the change in length of the cable caused by the car?

The mobile shown in the figure is perfectly balanced, and the horizontal supports have insignificant masses. What must be the masses of the suspended objects $m _ { 1 } , m _ { 2 } , \text { and } m _ { 3 }$ to maintain balance?