Question

While a block slides forward 1.35 m, a force pulls back at a 135 direction, doing -17.8 J of work. what is the magnitude of the force?(unit=N)PLEASE HELP

Answer 1

18.6467 N

Explanation:

       The Work done by any force is defined as the force applied times the displacement of point of application of force in the direction of force.

       This is better represented as a scalar product of Force vector and displacement vector.

       $Work\textrm{ = }\vec{F}.\vec{s}$

Here, the angle between force and displacement is $145^{o}$.

       $Work=|F||s|\cos\theta$

       $-17.8\textrm{ J = }|F|\times 1.35\textrm{ }m\times cos(135^{o})$

       $|F|=18.6467N$

∴ Magnitude of force = $18.6467N$