một vật dao động điều hòa có độ lớn vận tốc cực đại là 31.4cm/s. lấy pi=3.14. tốc độ trung bình của vật trong một chu kì dao động

The percent efficiency of a machine can never be 100% (or greater), because in the real world some energy is always converted into a. heat b. work c. input force d. output force

Aturntable a is built into a stage for use in a theatrical production. it is observed during a rehearsal that a trunk b starts to slide on the turntable 10 s after the turntable begins to rotate. knowing that the trunk undergoes a constant tangential acceleration of 0.31 m/s2, determine the coefficient of static friction between the trunk and the turntable.

In an experiment, how can i change human errors? be specific.