Question

*** Please answer ALL three questions including question 1, question 2 that also comes with part A and B, and finally question 3. ***

1) A car rides on four wheels that are connected to the body of the car by spring assemblies that let the wheels move up and down over bumps and dips in the road. When an 80 kg person sits on the left front fender of a small car, this corner of the car dips by about 1 cm. Treating the spring assembly as a single spring, what is the approximate spring constant?

2) Dynamic climbing ropes are designed to noticeably stretch under load to lessen the forces in a fall.

A) A 20 m length of climbing rope is supporting a weight and stretches by 40 cm. This 
single rope is replaced by a doubled rope—two pieces of rope next to each other. How 
much does the doubled rope stretch? 


B) A 20 m length of climbing rope is supporting a climber and stretches by 120 cm. When 
the climber is supported by a 40 m length of rope, by how much does the rope stretch? 


3) Static climbing ropes are designed to be relatively stiff, stretching less than dynamic ropes. To meet a certain specification, an 11-mm-diameter rope must experience a maximum elongation of 2.5% when supporting a 75 kg load. What is the minimum Young’s modulus?

Answer 1