The eficiency of a simple machine can never be 100% why?
1 answer:
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Answer:
Explanation:
Time taken by stone to cover horizontal distance
where t is time, h is height of whirling the stone in horizontal circle, g is gravitational constant, Substituting h for 2.1 m and g for 9.81
= 0.654654 seconds
t=0.65 s
Velocity, v= distance/time
v=10/0.65= 15.27525 m/s
v=15.3 m/s
where r is radius of circle, substituting r with 1.1m
Therefore, centripetal acceleration is
See the graph in attachment
Explanation:
In this problem we have to draw a velocity-time graph for an object travelling initially at -3 m/s, then slowing down and turning around.
In the graph, we see that the initial velocity at time t = 0 is
and it is negative, so below the x-axis.
Later, the object slows down: this means that the magnitude of its velocity increases, therefore (since the velocity is negative) the curve must go upward, approaching and reaching the x-axis (which corresponds to zero velocity).
After that, the object's velocity keep increasing, but now it is positive: this means that the object is travelling in a direction opposite to the initial direction, so it has turned around.
Learn more about velocity:
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