The radiation from a particle traversing with varying velocity through a plate in straight motion (along the normal to its surface) has been investigated. It is assumed that the particle coordinate (inside the plate) is an arbitrary monotone function of time. The calculations are based on appropriate exact solutions of the Maxwell equations. It was shown that as a result of variation of particle velocity inside the plate (e.g., due to its slowing-down) the spectralangular distribution of Cherenkov radiation generated by the particle inside the plate may be essentially affected. Possible practical application of this phenomenon is discussed.