A robot standing on a cliff shoots a ball upwards with an initial speed of 30 m/s. What is the height of the cliff given that th
e ball reaches the bottom of the cliff 8 s after the shoot? (Take g = 10 m/s^2 and the height of the robot is negligible.)
A 25 m
B 45 m
C 80 m
D 145 m
A 25 m
B 45 m
C 80 m
D 145 m
1 answer:
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Answer:
the tangential velocity of the student is 4.89 m/s.
Explanation:
Given;
the radius of the circular path, r = 3.5 m
duration of the motion, t = 4.5 s
let the student's tangential velocity = v
The tangential velocity of the student is calculated as follows;
Therefore, the tangential velocity of the student is 4.89 m/s.
The speed of the object increases
Explanation:
We can answer this question by applying the work-energy theorem, which states that the work done on an object is equal to the change in kinetic energy of the object. Mathematically:
where
W is the work done on the object
are the final and initial kinetic energy of the object, respectively
m is the mass of the object
v is its final speed
u is its initial speed
In this case, the force does a positive amount of work on the object, so
This also implies that
And so
And therefore
which means that the speed of the object increases.
Learn more about work:
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