Answer:
![\boxed{\sf Kinetic \ energy \ (KE) = 85 \ J}](https://tex.z-dn.net/?f=%20%5Cboxed%7B%5Csf%20Kinetic%20%5C%20energy%20%5C%20%28KE%29%20%3D%2085%20%5C%20J%7D%20)
Given:
Mass (m) = 6.8 kg
Speed (v) = 5.0 m/s
To Find:
Kinetic energy (KE)
Explanation:
Formula:
![\boxed{ \bold{\sf KE = \frac{1}{2} m {v}^{2} }}](https://tex.z-dn.net/?f=%20%5Cboxed%7B%20%5Cbold%7B%5Csf%20KE%20%3D%20%20%5Cfrac%7B1%7D%7B2%7D%20m%20%7Bv%7D%5E%7B2%7D%20%7D%7D)
Substituting values of m & v in the equation:
![\sf \implies KE = \frac{1}{2} \times 6.8 \times {5}^{2}](https://tex.z-dn.net/?f=%20%5Csf%20%5Cimplies%20KE%20%3D%20%20%5Cfrac%7B1%7D%7B2%7D%20%20%5Ctimes%206.8%20%5Ctimes%20%20%7B5%7D%5E%7B2%7D%20)
![\sf \implies KE = \frac{1}{ \cancel{2}} \times \cancel{2} \times 3.4 \times 25](https://tex.z-dn.net/?f=%20%5Csf%20%5Cimplies%20KE%20%3D%20%5Cfrac%7B1%7D%7B%20%5Ccancel%7B2%7D%7D%20%20%5Ctimes%20%20%5Ccancel%7B2%7D%20%5Ctimes%203.4%20%5Ctimes%2025%20)
![\sf \implies KE =3.4 \times 25](https://tex.z-dn.net/?f=%20%5Csf%20%5Cimplies%20KE%20%3D3.4%20%5Ctimes%2025%20)
![\sf \implies KE = 85 \: J](https://tex.z-dn.net/?f=%20%5Csf%20%5Cimplies%20KE%20%3D%2085%20%5C%3A%20J)
D) decreasing the temperature lowers the average kinetic energy of the reactants.
Static equilibrium means that all forces are equal, so make this easiest you want to break F1 into it's horizontal and vertical components. As there are no other forces acting in the horizontal, we know the horizontal component of F1 is 40N. This allows the vertical component to be found using pythagorus theorem. After finding the vertical and horizontal components, you just have to add the vertical components to find the difference between the up and down.