Ahe-ne laser emits radiation with second by =633nm. how many photons are emitted per wavelength a laser with a power of 1 mw?

Ababy stroller is a rest on top of a hill which is 10 m high. the stroller and baby have a mass of 20 kg. what is the potential energy of the baby and stroller?

Beryl states that insulation with the smallest possible thermal conductivity is best to keep a house warm in winter, but worst for keeping a house cool in summer. sapphire insists the reverse is true: low thermal conductivity is good in the summer, but bad in the winter. which one, if either is correct? a. beryl, because low thermal conductivity results in low heat transfer. b. beryl, because low thermal conductivity results in high heat transfer. d. sapphire, because low thermal conductivity results in high heat transfer. e. neither, because low heat transfer is desirable both in summer and in winter.

An object that weighs 75n is pulled on a horizontal surface by a horizontal pull of 50 n to the right. the friction force on this object is 30 n to the left. what is the acceleration of the object?