Remember Rover from the Application

Remember Rover from the Applications section of the first chapter? He
was flying through the air in your car after you slammed on the brakes. As
he flew through the air, foremost in your mind had to be the question,
“When was he accelerating and when not?” When you slammed on the
brakes, Rover was the only one who didn’t accelerate. The car accelerated
because it changed speed. By virtue of your seat belt, which exerted a force
on you, you also accelerated. By the way, it doesn’t matter whether you
speed up or slow down; it’s always called acceleration. And yes, that is a bit
confusing. Now Rover just kept on doing whatever he was doing—his velocity
stayed the same. Until he hit the dash, of course.

Hasil (Bahasa Indonesia) 2:

Ingat Rover dari Aplikasi bagian dari bab pertama? Dia
sedang terbang di udara di mobil Anda setelah Anda menginjak rem. Seperti
ia terbang di udara, terutama dalam pikiran Anda harus menjadi pertanyaan,
"Kapan dia mempercepat dan kapan tidak?" Ketika Anda menginjak
rem, Rover adalah satu-satunya yang tidak mempercepat. Mobil dipercepat
karena berubah kecepatan. Berdasarkan sabuk pengaman, yang diberikan kekuatan
pada Anda, Anda juga dipercepat. By the way, tidak peduli apakah Anda
mempercepat atau memperlambat; itu selalu disebut percepatan. Dan ya, itu adalah sedikit
membingungkan. Sekarang Rover hanya terus melakukan apa pun yang ia lakukan-nya kecepatan
tetap sama. Sampai dia memukul dasbor, tentu saja.