một vật dao động điều hòa với phương trình x= 4cos(πt+π/6) . tìm tất cả những thời điểm vật đi qua vị trí cân bằng

What is the role of the ocular lens?

The car hoist allows the car to be driven onto the platform, after which the rear wheels are raised. if the loading from both rear wheels is 1380 lb, determine the force in the hydraulic cylinder ab. neglect the weight of the platform itself. member bcd is a right-angle bell crank pinned to the ramp at c. the force is positive if in tension, negative if in compression.

True or false: the cycle of seasons on the earth is caused by the tilt of the earth on its axis toward and away from the sun.