Section 6.2 1. Once it starts moving, a storage chest with a mass of 5 kg requires a force of 9.8 N to slide it across a floor. What is the coefficient of sliding friction between the chest and the floor?
2. The rolling and static coefficients of friction for a monorail’s wheel and the one-bar “track” on which it runs are 0.77 and 0.17. Which is which and why?
4. The force of static friction is zero between two objects before an attempt is made to push one of them. Is the force of static friction an example of a force that does not occur in an action-reaction pair with another force? Why or why not?
Section 6.3 1. Why are a bicycle rider waiting for a traffic light to change and a motorcycle travelling on the cross street at a constant speed of 50 km/hr both in equilibrium?.
2. Two springs have the same spring constant. Spring A is extended by 3 cm; Spring B is compressed 3 cm. Which deformed spring stores more energy?
3. Two springs require a force of 100 N to stretch them. Spring X is stretched 5 cm, and Spring Y is stretched 5 mm. Which spring is “stiffer”, and how do their spring constants compare?
4. A 500-kg flexible foot bridge is attached to two support structures on either side of a creek gorge. Each structure cansupport 1,000 kg. How much weight can the bridge support?