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kaloyan
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- Homework Statement
- Consider the situation in the attached photo. The kinetic energy in A is 10 J, in B is 30 J. What is the kinetic energy in C?
- Relevant Equations
- no equations
Consider the situation in the attached photo. The kinetic energy in A is 10 J, in B is 30 J. What is the kinetic energy in C?
Using that the mechanical energy is the sum of potential energy ##(E_p=mgh)## and kinetic energy ##(E_k=\dfrac{mv^2}{2})##, we get that the mechanical energies in ##A,B,C## are ##E_A,E_B,E_C##, respectively: $$E_A=10J + mg(3h+h_2)$$ $$E_B=30J + mg(h+h_2)$$ $$E_C=E_{k_c}+mgh_2$$ They must be equal. In other words: $$10J + mg(3h+h_2)=30J + mg(h+h_2)=E_{k_c}+mgh_2$$
Using that the mechanical energy is the sum of potential energy ##(E_p=mgh)## and kinetic energy ##(E_k=\dfrac{mv^2}{2})##, we get that the mechanical energies in ##A,B,C## are ##E_A,E_B,E_C##, respectively: $$E_A=10J + mg(3h+h_2)$$ $$E_B=30J + mg(h+h_2)$$ $$E_C=E_{k_c}+mgh_2$$ They must be equal. In other words: $$10J + mg(3h+h_2)=30J + mg(h+h_2)=E_{k_c}+mgh_2$$
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