Một vật dao động điều hoà theo phương trình x = 12cos(4πt) (cm), biên độ dao động của vật là

An object thrown vertically upward from the surface of a celestial body at a velocity of 36 m/s reaches a height of sequalsminus0.9tsquaredplus36t meters in t seconds. a. determine the velocity v of the object after t seconds. b. when does the object reach its highest point? c. what is the height of the object at the highest point? d. when does the object strike the ground? e. with what velocity does the object strike the ground? f. on what intervals is the speed increasing?

Many machines- including inclined planes such as ramps- increase the strength of the force put into the machine but decrease the distance over which the force is applied. true or false

In the illustration, which two simple machines are being used to enable the student to reach the door? a. inclined plane and pulley b lever and wheel-and-axle c pulley and lever d wheel-and axle and inclined plane