What is the change in internal energy if 20 J of heat is released from a system and the system does 50 J of work on the surroundings?

A.-80 J

B.-20 J

C. 80 J

D. 20 J

Which best contrasts electric doorbells and audio speakers? Doorbells involve rapid changes in the direction of current, and speakers do not. Speakers involve rapid changes in the direction of current, and doorbells do not.

How do I solve for time if I have initial velocity and final speed?

What distance formula

A person who is described as intersex is

A person hums into the top of a well (tube open at only one end) and finds that standing waves are established at frequencies of 40.6, 67.7, and 94.7 Hz. The frequency of 40.6 Hz is not necessarily the fundamental frequency.

A space vehicle is traveling at 2980 km/h relative to Earth when the exhausted rocket motor is disengaged and sent backward. The relative speed between the motor and the command module is then 94 km/h.

He is the chemical symbol for which element? Select one: a. hydrogen b. hassium c. helium d. hafnium

If two electrons in the same atom have the same four quantum numbers, then they must have the same energy. a. trueb. falsec. They cannot both have the same four quantum numbers.

A 6.0 m wire with a mass of 50 g, is under tension. A transverse wave, for which the frequency is 810 Hz, the wavelength is 0.40 m, and the amplitude is 4.0 mm, is propagating on the wire.

Which has the greater change in momentum, a 50 gram clay ball that strikes a wall at 1 m/s and sticks or a 50 gram superball that strikes the wall at 1 m/s and bounces away at 0.8 m/s. Explain?