Question

Turn the argument around. If the object falls to the Earth starting from rest a great distance away, what is the speed with which it will hit the upper atmosphere? (Actually, a comet or asteroid coming from a long distance away might well have an even larger speed, due to its interaction with the sun.) Small objects vaporize as they plunge through the atmosphere, but a very large object can penetrate and hit the ground at very high speed. Such a massive impact is thought to have killed off the dinosaurs.

Short answer

The object will hit the Earth's upper atmosphere with speed $1.12\times {10}^{4}m/s$.

Step-by-step solution

Given Data

In a closed system, i.e., a system that is isolated from its surroundings, the total energy of the system is conserved.

Definition of Energy conservation law

The law of conservation of energy states that energy can neither be created nor be destroyed. Although, it may be transformed from one form to another. If you take all forms of energy into account, the total energy of an isolated system always remains constant. All the forms of energy follow the law of conservation of energy. In brief, the law of conservation of energy states that

In a closed system, i.e., a system that is isolated from its surroundings, the total energy of the system is conserved.

Determine the speed of the object

If an object needs to have speed$1.12\times {10}^{4}m/s$ in order to leave the Earth and go far away, then, according to the Energy conservation law, the object goes from very far away and is falling to the Earth, it will hit the upper atmosphere with the same speed$1.12\times {10}^{4}m/s$.

Therefore, according to the energy conservation law, the object will hit the Earth's upper atmosphere with speed $1.12\times {10}^{4}m/s$.