355 Preflight #32

Lesson 32
Scattering Wrap-up, Intro to Motion in Noninertial Reference Frames

Name:faculty

Section:M2

Start Time:14:33:46

Instructor:pate

Course:355

1) Suppose you bombard a sample of unknown substance(s) with a beam of helium nuclei ("alpha particles") of known energy. You place a detector at a certain angle as shown in the figure. The detector allows you to log each particle (and its energy) that hits it, so it measures the number of events per time (and their energies) at a given scattering angle.

Use this setup to describe what you think s(y) actually represents.
The detector, placed at a given scattering angle, will clearly record some scattering events. These will be caused by alpha particles that "bounce back" into the detector after scattering off of the target. Is it possible for these "bounced back" alpha particles to have different energies from one another? Please briefly explain.
What might be a practical use for such an apparatus/experiment?

2) Estimate the centrifugal acceleration (due to the Earth's rotation) of a bug sitting on the surface of the Earth, at the equator. How does this centrifugal acceleration compare to the gravitational acceleration on the bug at the surface of the Earth?

3) You've decided to go back to the playground where the children were playing on the merry-go-round a few weeks ago. There are once again children there. One little girl is sitting near the outer edge of the merry-go-round with a ball. She is facing the center of the merry-go-round. While the merry-go-round is spinning, she rolls the ball toward the center of the merry-go-round, as shown in the figure. Which way does the ball seem to deflect to her?

to the left if the merry-go-round is rotating clockwise as seen from above
to the right if the merry-go-round is rotating clockwise as seen from above
to the left if she is in the northern hemisphere (and independent of the merry-go-round's rotation sense)
to the right if she is in the northern hemisphere (and independent of the merry-go-round's rotation sense)

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