A driver is speeding at 40 m/s when she slams on the brakes of her car. She skids for a distance of 67 meters before coming to a stop. What is the acceleration of the car? * A. -11.94 m/s²
B. 0.3m/s²
C. 53600 m/s²
D. -16.42 m/s²

A

Explanation:

This question can be answered by using the basic kinematic equation v²=v₀²+2ax, where v² is the final velocity, or 0m/s in this case because the car comes to a stop, v₀² is the initial velocity, or 40m/s, and x is the change in the horizontal position, or 67 meters here. When you plug in these values and solve for a (acceleration) you get a value of -11.94m/s².

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle

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