# Problem: A rock is thrown downward from the top of a 40.0-m-tall tower with an initial speed of 12 m/s. Assuming negligible air resistance what is the speed of the rock just before hitting the ground? (a) 28 m/s (b) 30 m/s (c) 56 m/s (d) 784 m/s (e) More information is needed.

###### FREE Expert Solution

In this problem, we are launching an object downward. Thus we'll use kinematics.

Uniform accelerated motion (UAM) equations, a.k.a. "kinematics equations":

98% (229 ratings) ###### Problem Details

A rock is thrown downward from the top of a 40.0-m-tall tower with an initial speed of 12 m/s. Assuming negligible air resistance what is the speed of the rock just before hitting the ground?

(a) 28 m/s (b) 30 m/s (c) 56 m/s (d) 784 m/s (e) More information is needed.

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Our tutors have indicated that to solve this problem you will need to apply the Vertical Motion and Free Fall concept. You can view video lessons to learn Vertical Motion and Free Fall. Or if you need more Vertical Motion and Free Fall practice, you can also practice Vertical Motion and Free Fall practice problems.

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Based on our data, we think this problem is relevant for Professor Jerousek's class at UCF.