Cho cơ hệ như hình vẽ. Bỏ qua khối lượng các ròng rọc và ma sát giữa các mặt tiếp xúc.
(a) Tìm mối liên hệ giữa a1 và a2.
(b) Xác định biểu thức các lực căng dây, a1, a2

Suppose that 27 j of work is needed to stretch a spring from its natural length of 6 m to a length of 9 m. (a) how much work is needed to stretch the spring from 12 m to 14 m? j (b) how far beyond its natural length will a force of 78 n keep the spring stretched?

You are driving to the grocery store at 20 m/s. you are 110m from an intersection when the traffic light turns red. assume that your reaction time is 0.50s and that your car brakes with constant acceleration. how far are you from the intersection when you begin to apply the brakes? what acceleration will bring you to rest right at the intersection? how long does it take you to stop after the light changes? the known values: vi=20m/s xi=110m t=.50s vf=0m/s xf=0m a=?

Based on this activity, is kinetic energy always transformed into potential energy?