The decline bench press gives you have a limited range of motion. You can use more weight because of both mechanical advantage and less total work being performed. By only bringing the bar down to your lower chest, you severely limit the distance you move the bar.
The time difference that you sense is due to the way sound and light travel. Light travels extremely fast (300,000,000 m/s). In fact, it is faster than anything else. Sound travels at a measly 343 m/s through air. Therefore we can see light in an instant, but it takes a while to hear thunder. Sound has another disadvantage because it tends to bounce off molecules in the air. This makes the sound travel in all different directions.
Â­As you can see, the speed of sound changes depending on the temperature and the humidity; but if you want a round number, then something like 350 meters per second and 1,200 feet per second are reasonable numbers to use.So sound travels 1 kilometer in roughly 3 seconds and 1 mile in roughly 5 seconds.When you see the flash of a lightning bolt, you can start counting seconds and then divide to see how far away the lightning struck.As you can see, the speed of sound changes depending on the temperature and the humidity; but if you want a round number, then something like 350 meters per second and 1,200 feet per second are reasonable numbers to use.