PhysicsBowl 2018 Q21

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PhysicsBowl 2018

21) This question is a simple kinematics problem. We want to know the final speed of an object dropped from rest that hits the ground in 2.5 seconds.

where F[g] is gravitational force, t is time, v is velocity, and h is height

Since air resistance is neglected, the only gravity acts on the object. Thus, using our acceleration as g, we can solve this problem.

Where v is velocity, a is acceleration, and t is time

Remember that this question asks for the speed of the object. This is why we take only the magnitude of the velocity.