The position of a particle moving on the x- axis is x= 7.8 + 9.2t -2.1t³ where x is in meters and t is in seconds. What's it's velocity at t= 3.5 seconds and is the velocity constant or continuously changing?​

Asteam power plant operates on an ideal reheat rankine cycle between the pressure limits of 15 mpa and 10 kpa. the mass flow rate of steam through the cycle is 12 kg/s. steam enters both stages of the turbine at 500°c. if the moisture content of the steam at the exit of the low-pressure turbine is not to exceed 10 percent, determine (a) the pressure at which reheating takes place, (b) the total rate of heat input in the boiler, and (c) the thermal efficiency of the cycle. also, show the cycle on a t-s diagram with respect to the saturation lines. (2.15 mpa; 45.0 mw; 42.6%)

If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.

If a rock weighing 54 n is submerged in a liquid with a density exactly twice that of water, what will be its new apparent weight reading in the liquid?