Answer:
Resultant displacement of the child is 5 m.
Explanation:
It is given that, a child walks 5.0 meters north, then 4.0 meters east, and finally 2.0 meters south.
We have to find the magnitude of displacement of the child after the entire walk. The attached figure shows entire journey of the child. Displacement of an object is equal to the shortest path covered by it. Here, AM shows the net displacement. It can be calculated using Pythagoras theorem as :
Since, AB = 5 m So, OA = 3 m and BC = OM = 4 m
⇒ AM = 5 m
Hence, the resultant displacement of the child after the entire walk is 5 m.
The correct answer is:
the distance of the orbiting object to Earth.
In fact, we know that the gravitational force that keeps the object in circular motion around the Earth is equal to the centripetal force, so we can write:
If we re-arrange the equation, we find an expression for the tangential speed of the object:
and we see that it depends on 3 quantities: G, M (the mass of the Earth) and r (the distance of the object from the Earth).
The centripetal acceleration of an object is given by the relation,
where Ac = centripetal acceleration =
R = radius of rotation = 15 m
V = speed of astronaut
Hence,
solving this we get, V = 38.34 m/s