Here's why:
* The vowel sound in "pulse" is similar to the "u" in "cup" or "up". This is a short vowel sound.
* Long vowel sounds are typically associated with a vowel followed by a consonant and then a silent "e" at the end of the word. For example, "cube", "hope", or "kite".
Let me know if you have any other words you'd like to check!