A rock is thrown straight down with an initial velocity of 17.5 m/s from a cliff.What is the rock's displacement after 2.0 s? (Acceleration due to gravity is 9.80 m/s². ) A) 28 m B) 49 m C) 55 m D) 64 m

Question

Quizplus · Accepted Answer

Using the equation: 
d = Vit + 1/2 at^2 
where d = displacement, Vi = initial velocity, a = acceleration, and t = time, we can plug in the given values: 
d = (17.5 m/s)(2.0 s) + 1/2 (9.80 m/s^2) (2.0 s)^2 
d = 35.0 m + 1/2 (9.80 m/s^2) (4.0 s^2) 
d = 35.0 m + 19.6 m 
d = 54.6 m 
Round this to the nearest whole number and we get a displacement of about 55 meters. Therefore, the correct answer is C.

A Rock Is Thrown Straight Down with an Initial Velocity