Answer
See the detailed answer below.
Work Step by Step
The given formula seems to be a conservation of energy equation.
The first term is kinetic energy while the second term seems to be thermal energy done by a friction force that has a coefficient of friction of 0.15, and the last term is the work done by a tension force.
a) A box of mass 2 kg was initially at rest on a rough surface that has a coefficient of friction between it and the box of 0.15. A kid came to tie a rope on the box so he can pull it forward. The tension on the rope while moving it at a horizontal distance of 2 m is $T$ and it is constant throughout the whole trip. The speed of the box at the end of the 2-m trip was 4 m/s, Find the tension force.
b) See the figure below.
c) Solving the given formula for $T$;
$$T=\dfrac{\frac{1}{2}
(2)(4^2)+(0.15)(2)(9.8)(2)}{2}\approx \color{red}{\bf 11}\;\rm N$$
