Please help.: Sliding from left to right in a straight line on a horizontal steel surface, an aluminum block weighing 20 newtons
2 answers:
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Answer:
<em>147.3 N</em>
Explanation:
Two-Mass Systems
To solve a system where two masses are interacting with each other, we must set up the formulas by applying Newton's second law for each mass. Then, we find the required magnitudes by solving a system of equations.
Our system consists of a hanging object with mass attached to an object of mass
lying in a table which applies a known friction force of
. We also know the system accelerates at
. The situation is pictured in the image below.
Analyzing the forces acting upon mass we have, in the horizontal axis, where movement is taking place:
Where T is the rope's tension force. Now taking the vertical axis of the second mass, we have
The acceleration is negative since it's directed downwards, contrary to the positive default direction (right and up). Subtracting both equations:
Solving for
We know that
so, the above formula becomes
Rearranging and factoring
Solving for
Let's use our known data
Finally, we compute the object's weight
