A certain car needs 25 feet to come to a stop after the brakes are applied at 20 MPH. Braking distance d (in feet) is directly proportional to the square of the speed s (in MPH). What distance is needed to stop this car after the brakes are applied at 60 MPH.

Question

A certain car needs 25 feet to come to a stop after the brakes are applied at 20 MPH.  Braking distance d (in feet) is directly proportional to the square of the speed s (in MPH).  What distance is needed to stop this car after the brakes are applied at 60 MPH.

anonymous · Answer

if you know how to do it please help me!!

anonymous · Answer

it's a ration right
for 20MPH it needs 25 feet
and for 60MPH it needs X

anonymous · Answer

so divide 60 by 20 and multiply that by 25

anonymous · Answer

should be 75 feet

anonymous · Answer

ok thanks  what about this one
The volume of a gas varies directly as its temperature and inversely as its pressure.  At a temperature of 100 Kelvin and a pressure of 15 kilograms per square meter, the gas occupies a volume of 20 cubic meters.  Find the volume at a temperature of 150 Kelvin and a pressure of 30 kilograms per square meter

anonymous · Answer

that's chemistry and there's a rule for that but I can't remember it
sorry

anonymous · Answer

its not chemistry its pre cal

anonymous · Answer

it's just like what we did in chem
I bet someone in Chemistry can help you and i'll try to look for the formula

anonymous · Answer

kk thanks