A hockey puck slides off the edge of a platform with an initial velocity of 20 m/s horizontally. The height of the platform above the ground is 2.0 m.
What is the magnitude of the velocity of the puck just before it touches the ground? You can neglect air resistance.
A) 22 m/s B) 25 m/s C) 24 m/s D) 6.3 m/s E) 21 m/s
Question 2
What was Einstein's main reason for proposing the principle of the constancy of lightspeed?
A) This principle followed from his conclusions regarding the relativity of time and space.
B) His own observations of such simple phenomena as reflection and refraction convinced him that light must have the same speed for all observers.
C) The Michelson-Morley experiment showed that every observer observes the same speed for any lightbeam.
D) He believed that Maxwell's theory of electromagnetism should obey the principle of relativity.
E) He believed that conservation of energy should be obeyed in every nonaccelerated reference frame.