The Burj Khalifa in Dubai is the world's tallest building. The structure is 828 m 828 m (2716.5 ft) and has more than 160 storie
s. A tourist is obviously using the elevator to reach their hotel room and after a long ride finally arrives at the correct floor, where the tourist has − 2.01 × 10 5 J −2.01×105 J of potential energy. If the 86.4 kg 86.4 kg tourist has zero potential energy at the top of the building, how high ( h ) (h) is the hotel room from the ground? The acceleration due to gravity is 9.81 m / s 2 .
The momentum before is zero because nothing is moving. Note that because momentum is a conserved vector, the total momentum after the shot is also zero. You just have to add the products of mass and velocity in opposite directions. So the answer is zero
