Aspeed truck locks it’s brakes and it skids to a stop. if the truck’s total mass were doubled, it’s skidding distance would be?

The skidding distance would be doubled

Explanation:

When the truck applies the brakes and slows down, its motion is a uniformly accelerated motion, so its skidding distance can be found by using the suvat equation

where

v = 0 is the final velocity (zero since the truck comes to a stop)

u is the initial velocity

a is the acceleration

s is the skidding distance

The acceleration can also be written as

where F is the force applied by the brakes and m the mass of the truck. Substituting into the previous equation,

We see that the skidding distance is proportional to the mass: therefore, if the mass of the truck is doubled, the skidding distance will double as well.

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form