Light gates are more reliable. When using a manual stop watch, it is difficult to stop it at an exact time. A light gate is able to detect when an object passes through a 'gate' with the infrared transmitter and receiver.
Around 27 satelites is used for GPS technology
a . true hardness and density are physical properties
1. Humidity cannot be used to predict rain.
2. I'm pretty sure it's weather but I'm not 100% sure. Maybe like 89% sure.
3. Tempurature doesn't affect humidity.
4. Not sure but I think its the 3rd one
