Ultraviolet rays are used to _____.
2 answers:
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Answer:
0.128 s
Explanation:
We have to start by calculating the net force acting on the log. We have two forces:
- The constant pulling force, forward, of F = 2500 N
- The frictional force, backward
The frictional force is given by
where
is the coefficient of friction
m = 300 kg is the mass of the log
is the acceleration of gravity
Substituting,
So the net force acting on the log is
Now, we can find the acceleration of the log by using Newton's second law
where a is the acceleration. Re-arranging for a,
And finally we can find the time it takes for the log to reach a speed of
v = 0.5 m/s
by using the suvat equation:
where u = 0 is the initial speed and t the time. Solving for t,