Answer:
<em>0.3c</em>
<em></em>
Explanation:
The speed of Enterprise relative to Risa is 0.8c
Relative speed of both ships as measured from Enterprise is 0.5c
therefore, relative speed of Astra to Enterprise is 0.8c - 0.5c = <em>0.3c</em>
<em>this is also the relative speed with which Astra approaches the planet Risa since Enterprise's speed was calculated relative to Risa.</em>
Not at all. Density on its own is not sufficient
Answer:
30 metres.
Explanation:
Given that a red ball moves horizontally in a 30 m long tube.
Displacement is the distance travelled in a specific direction. It has both magnitude and direction.
Since the motion is horizontal, it moves is a certain direction.
Within the stipulation of time, the displacement will be the distance covered in the horizontal direction which is 30 metres.
Therefore, the displacement of the motion of the red ball is 30 metres.