The first planets around other stars were discovered

A) by Huygens, following his realization that other stars are Suns.
B) by Galileo following the invention of the telescope.
C) about a century ago.
D) in the 1990s.
E) in the 2010s.


D) in the 1990s.

Physics & Space Science

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The magnetic domains in a magnet produce a weaker magnet when the magnet is

A. dropped on a hard surface B. heated C. either of these answers D. neither of these answers

Physics & Space Science

The velocity of an object as a function of time is given by v(t) = -3.0 m/s - (2.0 m/s2 ) t + (1.0 m/s3 ) t2. Determine the instantaneous acceleration at time t = 2.00 s

A) -5.0 m/s2 B) 2.0 m/s2 C) -18 m/s2 D) -3.0 m/s2 E) 18 m/s2

Physics & Space Science

In an electron two-slit experiment, the slits are 15 ?m apart. If the first diffraction maximum lies at an angle of 5.0 × 10-7 rad, what is the momentum of the incoming electrons?

A) 4.4 × 10-23 kg?m/s B) 2.2 × 10-23 kg?m/s C) 11 × 10-23 kg?m/s D) 6.6 × 10-23 kg?m/s E) 8.8 × 10-23 kg?m/s

Physics & Space Science

Imagine a group of people standing in a circle. There are two ways that they can create a “wave”. One way is by placing the palms of their hands together. One person begins by pushing on the adjacent person's palm who, in turn, pushes on the next person's palm, etc. Another way is by adjacent people holding hands. One person lifts the other person's hand and then that person lifts the next

person's hand, etc. Which types of waves are represented by each case? 1.Both cases represent longitudinal waves. 2.The first case represents a transverse wave and the second case represents a longitudinal wave. 3.Both cases represent transverse waves. 4.The first case represents a longitudinal wave and the second case represents a transverse wave.

Physics & Space Science