Question

A 700-N man jumps out of a window into a fire net 10 m below. The net stretches 2 m before

bringing the man to rest and tossing him back into the air. The maximum potential energy of

the net, compared to its unstretched potential energy, is:

Answer 1

Answer:

The maximum potential energy of the net, compared to its unstretched potential energy, is:    $E_{mn} -E_{un} = 8400J$

Explanation:

From the question we are told that

   The  weight of the man is  $W_m = 700 \ N$

    The distance of the window to the net is  $d = 10 \ m$

    The distance stretched by net is  $D = 2 \ m$

Generally from the of conservation energy , the total energy is conserved

This implies that

      $E_m__{i} + E_{un} = E_m__{f}} + E_{mn}$

Where $E_m__{i}}$ is the initial potential energy of the , man which is mathematically evaluated as

         $E_m__{i}} = W_m * d$

Substituting values

       $E_m__{i}} = 700 *10$

       $E_m__{i}} = 7000 \ J$

And  $E_{un}$ is the unstretched potential energy of the net

 And  $E_m__{f}}$ is the final potential energy of the man which is mathematically evaluated as

           $E_m__{f}} = - W_m * D$

Substituting values  

          $E_m__{f}} = - 700 * 2$

          $E_m__{f}} = - 1400$

The negative show that the direction of the man  is against the direction of gravitational pull

And    $E_{mn}$ is  the maximum potential energy of the net when stretched

So the above equation becomes

            $7000 + E_{un} = - 1400 + E_{mn}$

So  

       $E_{mn} -E_{un} = 7000 + 1400$

        $E_{mn} -E_{un} = 8400J$