A man dressed in all black is walking down a country lane. Suddenly, a large black car with no lights on comes around the corner and screeches to a halt. How did the car’s driver know he was there?

this is tricky

Ahypothesis is? close agreement by competent observers of observations of the same phenomena. a guess that has been tested over and over again and always found to be true. an educated guess that has yet to be proven by experiment. the long side of a right triangle. a synthesis of a large collection of information that includes guesses.

1. jay fills a wagon with sand (about 20 kg) and pulls it with a rope 30 m along the beach. he holds the rope 25° above the horizontal. the rope exerts a 20-n tension force on the wagon. how much work does the rope do on the wagon?

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.