A rock is thrown straight up with an initial velocity of 15.0 m/s.Ignore energy lost to air friction.How high will the rock rise?
A)1.53 m
B)22.9 m
C)6.50 m
D)11.5 m

Question

Quizplus · Accepted Answer

Using the kinematic equation for displacement:
Δy = v₀t + 1/2at²
Since the rock is thrown straight up, the initial velocity and final velocity are both 0 m/s. Therefore, v₀ = 15.0 m/s and a = -9.81 m/s² (acceleration due to gravity). 
We want to find the maximum height, which occurs when the rock reaches its highest point and stops momentarily before falling back down. At this point, the final velocity is 0 m/s, so we can use this equation to find the time it takes to reach this maximum height:
v = v₀ + at
0 = 15.0 m/s + (-9.81 m/s²)t
t = 1.53 s
Using this value of time in the displacement equation:
Δy = (15.0 m/s)(1.53 s) + 1/2(-9.81 m/s²)(1.53 s)²
Δy = 11.5 m
Therefore, the rock will rise to a height of 11.5 m.

A Rock Is Thrown Straight Up with an Initial Velocity