The top pair of pliers failed to loosen a stubborn bolt, but the bottom pair successfully removed it. Because the contact between the bolt and the pliers working surface is less.
<h3>What is mechanical advantage ?</h3>
Mechanical advantage is a measure of the ratio of output force to input force in a system, it is used to obtained efficiency of the given mechanical machine.
The efficiency to open the stubborn bolt depends upon the contact between the working surface of the pliers and the bolt.
The contact between the bolt and the top pair of pliers working surface is less. Its mechanical advantage is less.
Hence, the top pair of pliers failed to loosen a stubborn bolt, but the bottom pair successfully removed it.
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Answer:
<h2>
206.67N</h2>
Explanation:
The sum of force along both components x and y is expressed as;

The magnitude of the net force which is also known as the resultant will be expressed as 
To get the resultant, we need to get the sum of the forces along each components. But first lets get the acceleration along the components first.
Given the position of the object along the x-component to be x = 6t² − 4;


Similarly,



Hence, the magnitude of the net force acting on this object at t = 2.15 s is approximately 206.67N
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