Unformatted text preview: ic energy, so
speed, where is the initial is the braking force, and is the stopping distance. Both masses have kinetic energy,
J, so they both travel the same distance before stopping. 4 (b) [4pt] A woman rides in the “Barrel of Terror” at a fair, which spins
up to a certain speed, and then the floor drops out below, leaving the
riders “stuck” to the walls as shown at the right. Which of the free
body diagrams below correctly shows the forces on the woman?
(A) (B) (C) (D) (E) Note: To get partial credit for a wrong choice, you have to label the force vectors.
The normal force supplies the centripetal acceleration:
The condition not to slip is that
but the question didn’t ask for that . . Friction balances the
This implies that
, (c) [4pt] A conservative force acts along the axis, given by
Which of the
following could represent its potential energy? (Units are not shown, but may be assumed to
(A) (B) (C) (D) By definition, the potential energy is for arbitrary Choosing gives answer (B). 5 (d) [4pt] A car can go from 0 to 1...
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