The gravitation field strength of Planet X is 10 times that of Earth's, as the object weight has increased 10 times. This is only possible if the planet is more massive or more dense (smaller diameter).
Basically the cheetah is running 31.5km/h faster than the gazelle. So to determone how long it will take to cover 9mm at that speed, you have to a lot of work. If you skip all of that work, the answer is 1.60m seconds
