Since sphere is performing pure rolling motion
So here the contact point of sphere with respect to inclined plane is always at rest.
This contact point will not move at any instant and and hence sphere will perform pure rolling.
So here we can say that sphere will have some friction force at the contact point but there is no displacement of that point.
So the work done by this static friction will always ZERO.


So there is no work done by friction on the sphere while it is in pure rolling.
The displacement of the train after 2.23 seconds is 25.4 m.
<h3>Resultant velocity of the train</h3>
The resultant velocity of the train is calculated as follows;
R² = vi² + vf² - 2vivf cos(θ)
where;
- θ is the angle between the velocity = (90 - 51) + 37 = 76⁰
R² = 8.81² + 9.66² - 2(8.81 x 9.66) cos(76)
R² = 129.75
R = √129.75
R = 11.39 m/s
<h3>Displacement of the train</h3>
The displacement of the train is the change in position of the train after a given period of time.
The displacement is calculated as follows;
Δx = vt
Δx = 11.39 m/s x 2.23 s
Δx = 25.4 m
Thus, the displacement of the train after 2.23 seconds is 25.4 m.
Learn more about displacement here: brainly.com/question/2109763
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Explanation:
The given data is as follows.
width = 100 m, speed = 3 m/s
So, minimum time required to cross the stream is calculated as follows.
t =
Also, in the same time the man has moved downstream by 50 meter.
Hence, distance traveled downstream is as follows.
d = velocity of river × t

= 
= 
= 1.5 m/s
Thus, we can conclude that the river is flowing by 1.5 m/s.
Answer:
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Explanation: