# A 3.5 kg projectile was launched vertically at 75m/s. The projectile reached a maxiumum height of 180m. How much energy was lost to heat while the projectile was rising?

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### 1 Answer

When an object travels in air it can lose its energy due to friction with air and heat will be generated.We can compare the energy at two levels to calculate the energy lost during travel.

If the starting horizontal level is the potential energy zero line (h=0) we can write the potential energy of maximum height wrt it.

Kinetic enrgy at start + Potential enrgy at start = Kinetic energy at maximum height + Potential energy at maximum height + Energy lost due to heat(H)

`1/2 xx 3.5 xx 75^2 + 0 = 0 + 3.5 xx 9.81 xx 180 + H`

`H = 9843.75 - 6180.3`

`H = 3663.45 J`

Therefore the energy loss due to heat is 3663.45.