Question

A student is testing the kinematic equations for uniformly accelerated motion by measuring the time it takes for light-weight plastic balls to fall to the floor from a height of 3m in the lab. The student predicts the time to fall using g as 9.80m/s² 

(A) The acceleration due to gravity is 70% greater than 9.80 m/s² but finds the measured time to be 35% greater. Which of the following is the most likely cause of the large percent error?  

(B) The acceleration due to gravity is 70% less than 9.80 m/s² at this location. 

(C) Air resistance increases the downward acceleration. at this location. 

(D) The acceleration of the plastic balls is not uniform. 

(E) The plastic balls are not truly spherical.

Answer 1

Correct option (D) The acceleration of the plastic balls is not uniform.

By process of elimination (A and B are unrealistic; C is wrong, air resistance should decrease the acceleration; E is irrelevant)