A device that spreads out effort over time

Nuclear fusion is the source of energy for stars. besides hydrogen, which other element is most likely also common in stars?

Imagine that you push on a large rock. at what point does your effort change the rock’s mechanical energy?

Abeaker with 2.00×102 ml of an acetic acid buffer with a ph of 5.000 is sitting on a benchtop. the total molarity of acid and conjugate base in this buffer is 0.100 m. a student adds 4.70 ml of a 0.360 m hcl solution to the beaker. how much will the ph change? the pka of acetic acid is 4.740.