A skilled ballet dancer appears to move in a seemingly floating motion, seeming to defy gravity in a grand jeté. Part of how this is done is by:
a. moving her arms and legs to keep her center of mass at the about same height above the ground.
b. moving her arms and legs to cause her center of mass to move upward while falling.
c. being supported from the ceiling by a hidden cable not visible to the audience.
d. moving her arms and legs so that as her center of mass moves, she keeps her head at the same height above the ground.
e. moving her arms and legs so that her center of mass is kept from accelerating downward.
d
You might also like to view...
For a system in simple harmonic motion, which of the following is the time required to complete a cycle of motion?
a. amplitude maximum b. period c. frequency d. wavelength
On pages 3 the chapter notes Europeans were unaffected by smallpox compared to Native American cultures. Why were they unaffected?
What will be an ideal response?
What does not happen as the molecular cloud collapses?
A: It heats up B: It fragments into many pieces C: It forms one huge star D: It speeds up because as clumps get closer, gravity attracts them more E: None of the above
Which of the following best sums up current scientific thinking about the nature of dark matter?
A) Most dark matter probably consists of weakly interacting particles of a type that we have not yet identified. B) Dark matter consists primarily of a mysterious form of energy that is causing the expansion of the universe to accelerate. C) There is no longer any doubt that dark matter is made mostly of WIMPs. D) Dark matter probably does not really exist, and rather indicates a fundamental problem in our understanding of gravity.