Question

Q1.

A vehicle suspension system consists of springs, together with shock absorbers to damp oscillations. The shock absorbers consist of an undersized piston in a cylinder filled with oil. A vehicle of mass 800 kg has such a suspension system. The vehicle’s body has to be lifted 100 mm before the wheels just leave the ground. In the following questions assume:

that the mass of the wheel is negligible compared to the mass of the car body

that the body oscillates with SHM when displaced on the suspension system

g = 10 ms-2. 1.

a) Assuming that the shock absorbers are not functioning, calculate the period of oscillation of the car body, when pushed down 50 mm and released.

b) Calculate the maximum values for the velocity and acceleration of the car body.

c) The shock absorbers are now repaired. Sketch two graphs on the same axes to compare the oscillations of the vehicle before and after the damping. Label axes carefully.

d) Discuss the energy changes occurring during the oscillations: a. When the shock absorbers are not working. b. When the shock absorbers are working.

e) The car drives along a road with raised speed bumps, separated by a distance of 20 m. Calculate the speed of the car necessary to cause maximum amplitude oscillations of the car body on the springs.

Answer 1