How would this student test the effects of gravity on objects with different masses? He would test objects with different masses but the same shape.

He would test how long it takes one object to fall from three different heights.
He would test differently shaped objects with the same mass.
He would perform any of the tests he tries, only once

To test the effects of gravity on objects with different masses but the same shape, the student could conduct an experiment as follows:

1. Gather objects of the same shape but varying masses, such as balls of different weights.
2. Set up a controlled experiment by dropping each object from the same height (e.g. a meter stick) and timing how long it takes for each object to hit the ground.
3. Repeat the dropping process multiple times for each object to ensure accuracy.
4. Record the time taken for each object to fall and observe any differences in the time depending on the mass of the object.
5. Analyze the results to determine the effect of gravity on objects with different masses but the same shape.

This experiment can help the student understand how gravity affects objects of varying masses but the same shape, and can provide insight into the relationship between mass and gravitational acceleration.