A puck of mass m moving at speed v on a horizontal, frictionless surface is stopped in a distance d because a hockey stick exerts on an opposing force of magnitude F on it.

F = (mv^2) / 2d

If the stopping distance d increases 40%, by what percent does the average force needed to stop the puck change, assuming that m and v are unchanged?

(Fnew - F) / F = ? %

Explanation:

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.

i had this question and the answer was 3.15 miles.

martina travels from school to her mom's office. from there, she walks to school. after school, she walks to the library and then to a friends house before finally ending back at home. find martina's total distance traveled.

a) 0 miles  

b) 0.4 miles  

c) 1 mile  

d) 3.15 miles