Work: Comparison and Relationship between Different Energies

PHY 100 & 103

Students will consider the relationship between the initial gravitational potential energy and the final kinetic energy of a ball rolled down a ramp onto a horizontal surface. Conclusions will be drawn from the comparison of the ball's final horizontal velocity as found in two different ways, first experimentally using distance and time measurements, and then theoretically by assuming that all of the potential energy gets converted to kinetic.

Equipment

Notes

The ruler provided for measuring the vertical height of the ball on the ramp must have the zero scale marking at the very edge. (The transparent, flexible rulers that are good for graphing typically do not.) Place the ball inside the masking tape to prevent it from rolling off the table.

Measure 10cm from the edge of the table and place the 0cm end of the ruler on the block there. Use the grain of the table to ensure the ruler is perpendicular to the end of the table. Secure the block to the table with a piece of masking tape on each side. Affix the plumb bob to the table next to the path of the ball. With the plumb bob ~2cm from the ground, use a piece of masking tape perpendicular to the string to affix the string a couple centimeters from the edge of the table, assuring that the tape does not cross the path of the ball. Pull the string taught and back over the piece of tape. With another piece of masking tape perpendicular to the string, affix both the string leading to the plumb bob and the string leading to the loose end to the edge of the table. Use one more piece of masking tape to cover the string on the table, forming with the other two pieces a capital i that is bent over the edge of the table.

Along with the initial apparatus set-up, supply a sufficient number of the appropriate paper procedure handouts for all of the lab sections that will use the set-up over the course of the week. Print the PDF, duplicate to double-sided pages, staple, and leave pile on instructor's table prior to first use of set-up.