Một vật dao động điều hòa trên một đường nằm ngang .Khi t=0 vật có vận tốc 40căn(3)cm hướng theo chiều dương quỹ đạo và đến lúc vận tốc bằng 0 lần thứ nhất nó đi được quãng đường 7,5cm. Biết rằng quãng đường vật đi được tronh hai chu kì dao động liên tiếp là 40cm. Viêt pt dao động điều hòa

Which property of fossils allow scientists to determine the relative rock ages..

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.