How do we know that there is an insignificant amount of dark matter in the solar system?
What will be an ideal response?
We can measure the distribution of mass in the solar system through analysis of the rotation curve, i.e. the velocity at which planets at different distances from the Sun rotate, in an analogous way to the rotation curves of galaxies. Since the rotation curve of the solar system decreases with increasing distance in the same way that we would predict for a central mass (the Sun), we infer that there are no "hidden" sources of gravitational mass in the solar system. Dark matter must be distributed over much larger scales.
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Once a theory has been tested thoroughly and is confidently believed by scientists, it becomes a ____________________
Fill in the blank(s) with correct word
You're lying on the sand on a breezy day when a pesky fly wishes to join you. The breeze is blowing at a steady 1 m/s. If the fly wishes to land on you it should hover over you while flying
A) about 2 m/s relative to the breeze. B) with the breeze at 1 m/s. C) against the breeze at 1 m/s. D) faster than 1 m/s but less than 2 m/s.
At t = 0, a particle is located at x = 25 m and has a velocity of 15 m/s in the positive x direction. The acceleration of the particle varies with time as shown in the diagram. What is the velocity of the particle at t = 5.0 s?
?
?
a.
+15 m/s
b.
?15 m/s
c.
+30 m/s
d.
0
e.
?1.2 m/s
A uniform pressure of 21 × 10^5 N/m2 is applied to all six sides of a copper cube. What is the percentage change in volume of the cube? (for copper, B = 14 × 10^10 N/m2)
a. 2.4 × 10^-2 % c. 8.4 × 10^-2 % b. 1.5 × 10^-3 % d. 0.5 × 10^-3 %