A pulley is used to lift a heavy mass from the floor to the platform. The IMA of the system is 5 and the AMA is 2.5. What is the
2 answers:
Answer:
efficiency= or 50%
Explanation:
IMA means Ideal Mechanical Advantage, and it indicates the ratio between the input forces and the output forces without taking into consideration the force needed to overcome friction. In pulleys, this is calculated by counting the number of ropes on the system that in this case is 5
IMA = 5
IMA is greater to the AMA because it doesn't take into consideration friction.
AMA is the Actual Mechanical Advantage, and it is the measure of the usefulness of the pulley, and it indicate the ratio between the output force (Fo) and the input force (Fi). The smaller this ratio, the less useful is the pulley, meaning, it does not simplify the job it is designed to ease, for example, a pulley that does not reduce the force needed to lift a load.
AMA=2.5
So from these two definitions, if we have the actual force ratio and the ideal force ratio, we basically have the "what it is" and the "what could be", a very crude representation of efficiency:
efficiency= or 50%
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Answer:
When have passed 3.9[s], since James threw the ball.
Explanation:
First, we analyze the ball thrown by James and we will find the final height and velocity by the time two seconds have passed.
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Note: The sign for the gravity is minus because it is acting against the movement.
Now we can find the velocity after 2 seconds.
Note: The sign for the gravity is minus because it is acting against the movement.
Now we can take these values calculated as initial values, taking into account that two seconds have already passed. In this way, we can find the time, through the equations of kinematics.
As we can see the equation is based on Time (t).
Now we can establish with the conditions of the ball launched by David a new equation for y (elevation) in function of t, then we match these equations and find time t
Then the time when both balls are going to be the same height will be when 2 [s] plus 1.9 [s] have passed after David throws the ball.
Time = 2 + 1.9 = 3.9[s]
Answer:
The time interval is 22.76 hr.
Explanation:
Given that,
Time = 30 hrs
Speed = 0.74c
We need to calculate the time interval measured in earth frame
Using formula of time dilation
Where, = time interval measured in earth frame
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Put the value into the formula
We need to calculate the proper time interval when the velocity is 0.86c
Using formula of time dilation
Hence, The time interval is 22.76 hr.