Using the Generalized Work Energy Principle, the puck is brought to rest by an external force and the system has no kinetic energy
#Denote the stopping distance and force required with a prime and observe from (i) that:
#If stopping distance increases by a factor of 79/50;
So F decreases by 36.71% . we expect force to reduce since the same amount of work is repeatedly done on the system over a long distance.
Assuming that m and v are unchanged.
For this case we have the following formula for the force:
For this case the new force would be given:
And for this case we can calculate the % like this:
And doing the algebra we got:
So then the force decrease 64.29 percent respect the original force.