Answer:
a) 3.0×10⁸ m
b) 0 m
Explanation:
Displacement is the distance from the starting position to the final position.
a) In half a year, the Earth travels from one point on the circle to the point on the exact opposite side of the circle (from 0° to 180°). The distance between the points is the diameter of the circle.
x = 2r
x = 2 (1.5×10⁸ m)
x = 3.0×10⁸ m
b) In a full year, the Earth travels one full revolution, so it ends up back where it started. The displacement is therefore 0 m.
Answer: precise
Explanation:
Three different people weight a standard mass of 2.00 g on the same balance. Each person obtains a reading of 2.32 g for the mass of the standard. These results imply that the balance that was used is precise.
Precision can be defined as the closeness of measured values to each other, for a measuring equipment it is the closeness of the values of readings obtained at different times to each other. It does not necessarily means the measurements are accurate(closeness to the actual value). Therefore, in the case above where three different people measured the same mass on the same balance, and each of them obtained the same value which is different from the standard value. We can say the balance used is precise because the three readings are the same.
Answer:
a.
b.
c. 
Explanation:
Use Gravitational Force:

Use values given to have the results.
b.

Use m as the mass of the Moon. Using values of a. and m you have the answer.
c.

Use M mass of the planet. Use value of a and Mass of Planet.
Answer:
sound wave-electrical wave-radio wave
Answer:
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