You've probably got this feeling while riding a roller coaster, that moment you suddenly fall to the bottom of a curve. It's like your heart and your stomach are being pulled down. I get this every day while going to work on my bike. On my way to work, there is this U-shaped curve in the street. Every time I get down to the bottom of this and then go up, I feel this tickling feeling which kind of makes me gasp for a moment. What's this feeling in English? If there is no particular word for this how do you describe it in English?
When you feel the bottom drop out, that's when you suddenly feel nothing beneath you and you are in a momentary free fall.
The bottom could drop out for someone who is being executed by hanging. The bottom could also drop out for the stock market, meaning the market is doing poorly. Or on an amusement ride, when the ride begins to drop rapidly, you could say, "I felt the bottom drop out."
If you are going over the top of a hill or rollercoaster quickly, you could feel your stomach drop or stomach sink. In actuality, it's probably the sensation of all your internal organs shifting slightly in your ribcage as your body defies gravity for a few seconds.
An article entitled How Roller Coasters Work says:
This is what gives you that unique sinking feeling in your stomach; your stomach is suddenly very light because there is less force pushing on it.
It's called motion sickness, although we usually limit that name to when the disagreement between what our optic and vestibular systems are telling us about our motion is in such violent disagreement that it induces nausea and discomfort instead of just minor lightheadedness and vertigo.
You could call it minor motion sickness, which it is, but people may probably think less of you for it either because they think you're whinging about a minor discomfort or because they think you should be able to handle a bike ride without incident. You could call it a sensation of kinetosis, since that means motion sickness but no one knows that. They'll just be impressed or put off by your vocabulary and leave it at that.
Finally, you could go with an expressive phrase but, pace Ringo, there really aren't any set ones. Remember, though, heart or stomach in my throat is usually talking about nervousness or fear rather than motion sickness.
The technical term is "Air Time".
"Air time" has a strange effect on your body because your body is not completely solid — it is composed of many parts. When your body is accelerated, each part of your body accelerates individually. The seat pushes on your back, the muscles in your back push on some of your organs and those organs push on other organs. That's why you feel the ride with your entire body. Everything inside is being pushed around.
How Stuff Works
In the context of amusement rides, air time, or airtime, refers to the time during which riders of a roller coaster or other ride experience either weightlessness or negative G-forces.
As Teacher KSHuang wrote in a comment:
Funnily enough, the phrase is exactly as you describe it: "It's like your heart and your stomach are being pulled down. It's like my heart drops into my stomach." That phrase generates more imagery, but if you want a single word, you could also say, "freefall."
You could use the word thrill, which means any sudden feeling of excitement or pleasant surprise. When you say it's a "tickling feeling which kind of makes me gasp for a moment", that definitely sounds like a thrill.
The word shock is similar, but that word means a sudden feeling of fear or unpleasant surprise.
It's hyperstimulation anxiety. I've had it my entire life, and it's awful. Anxiety medication helps a lot. You'll need to go to the doctor and be put on anxiety medication but it will help with these "panic attacks". Hyperstimulation anxiety is horrible to live with. But medication helps. Don't suffer, see a doctor.