A 2kg rock is dropped from a height of 10m and hits the ground going 11m/s. How much work was done by air resistance as it fell?
1 answer:
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Answer:
The rock's final speed at the required altitude will be 42.24 m/s.
Explanation:
Let's start by finding the initial vertical speed.
Vertical Speed = 1.61 * Sin (53.2°)
Vertical Speed = 0.8 m/s
We want to know the speed of the rock when it is at an altitude of 91 km.
The total displacement of the rock from its starting position will thus be equal to -91 km
We can use this in the following equation:
t = 4.3918 seconds
Thus it takes 4.3918 seconds to reach the required altitude. We can now find the speed as follows:
Thus the rock's final speed at the required altitude will be 42.24 m/s.
Answer:
The second vector points due West with a magnitude of 600N
Explanation:
The original vector points with a magnitude of 200N due east, the Resultant vector
points due west (that's how east/west direction can be interpreted, from east to west) with a magnitude of 400N. If we choose East as the positive direction and West as the negative one, we can write the following vectorial equation:
With the negative sign signifying that the vector points west.