You are asked to design spring bumpers for the walls of a parking garage. A freely rolling 1300 kg car moving at 0.62 m/s is to compress the spring no more than 0.072 m before stopping. What should be the force constant of the spring? Assume that the spring has negligible mass.

Explanation:

Given:

mass of the car,

parking speed of the car,

compression of spring bumpers on the walls,

Using the equation of motion:

where:

final speed of the car

acceleration of the car while compressing the spring (will be -ve since final velocity tends to zero)

(negative sign denotes that it is reducing the speed )

Now the force:

answer; (d) spontaneous processes are characterized by the overall conversion of order to disorder;

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.