I am an artificial indicator. I am liquid in state. I will change my colour in both acidic and basic solution. Who am I

A50.0-n box is sliding on a rough horizontal floor, and the only horizontal force acting on it is friction. you observe that at one instant the box is sliding to the right at and that it stops in 2.25 s with uniform acceleration. what magnitude force does friction exert on this box

Apatient has a history of poor nutrition. he has skin rashes, bleeding gums, and a cut that hasn’t healed in a long time. what vitamin deficiency most likely caused this symptom?

Two trains leave a station at the same time, train a travels at a constant speed of 16 m/s. train b starts at 8.0 m/s but accelerates constantly at 1.0 m/s squared. after 10.0 seconds, which train has the greater speed?