At which point do the riders feel centripetal acceleration?
w
x
y
or z

What would the difference of spectral lines emitted by hydrogen gas in distant galaxies which is normally found at a wavelength of 21 cm on earth, be observed at 21.1 centimeters?

What is the order of the moon, earth, and sun in a lunar eclipse and a solar eclipse?

A110-pound person pulls herself up 4.0 feet. this took her 2.5 seconds. how much power was developed? 0.13 hp 0.32 hp 2.0 hp 3.1 hp