Direct current is produced by

A man is parachuting when he accidentally drops his wallet. The man is falling at a rate of 2.2 m/s and the wallet hits the ground with a speed relative to the parachuter of 9.5 m/s.

A girl walks South at 2.7 m/s. What is the y component of her velocity

If an atom had 35 protons in the nucleus how many electrons will it have orbiting the nucleus?

What is the name of the theory that led to the development of the theory of plate tectonics

A violinist is tuning the A string on her violin by listening for beats when this note is played simultaneously with a tuning fork of frequency 440 Hz. She hears a beat frequency of 4 Hz.

What does the speed of sound depend on? A. Medium that the sound travels through B. Acoustics C. Frequency of the sound D. Loudness of the sound

Which of these is not a source of the shock waves that lead to protostars?

Which kind of information is known about a person if that person's DNA is in a database? A. how old the person is B. where the person was probably born C. some diseases the person might have D. whether the person is likely to commit a crime

A science teacher ran a marathon. After the race she showed her students the silver blanket she was given to keep her warm. A group of students investigated how the colour of the blanket affected how much infrared radiation is absorbed

Students asked to measure the temperature of a reaction beaker recorded the following temperatures. 103.7°C, 108.4°C, 105.8°C, 104.6°C The actual temperature is 105.1°C. Which measurement is the most precise