An automobile of mass 2000 kg is driven into a brick wall in a safety test. the bumper behaves like a hooke’s-law spring. it has an effective spring constant of 4 × 106 n/m, and is observed to compress a distance of 1.39 cm as the car is brought to rest. what was the initial speed of the automobile? answer in units of m/s.

0.621 m/s

Explanation:

Given

mass of automobile

Effective spring constant

compression in spring

Conserving Energy i.e. Kinetic energy of automobile=Elastic potential Energy of spring

potential energy is directly proportional to height.

more height = more potential energy.

greatest increase in height = greatest increase in potential energy

where are the points with the greatest increase in height ?

has to be c-e or d-e .