Question

In an experiment, students release a block from rest at the top of an inclined plane. The block slides down the plane through a vertical displacement h, and the students measure the speed v of the block using a photogate. The students expect the speed of the block at the end of this motion would be v=2gh−−−√. However, the measured v is significantly different.
Which of the following is the most probable source of error the students should cite in their lab report?

A) The accuracy of the photogate

B) Friction

C) Mass of the block

D) Variations of the force of gravity

E) Air resistance

Answer 1

Answer:

B) Friction

Explanation:

The main source of error is the omission of the effect from friction between block and incline, which is directly proportional to the mass of the block. The force of gravity is constant. The friction force dissipates part of the gravitational potential energy, generating a final speed less than calculated under the consideration of a conservative system. Air resistance is neglected at low speeds like this case.