What is the difference speed & velocity?

When an object moves in uniform circular motion, the direction of its acceleration is a) in the same direction as its velocity vector. b) in the opposite direction of its velocity vector c) is directed toward the center of its circular path. d) is directed away from the center of its circular path. e) depends on the speed of the object.

Your 249 ml cup of coffee is too hot to drink when served at 82 degree celsius. what is the mass of an ice cube taken from a -21 degree celsius freezer, that will cool your coffee to a pleasant 54 degree celsius. specific heat of the water is 4190 j/kg c, specific heat of ice is 2090 j/kg c, heat of fusion of ice is 3.33 x 10^5 j/kg

Henry, whose mass is 95 kg, stands on a bathroom scale in an elevator. the scale reads 830 n for the first 2.4 s after the elevator starts moving, then 930 n for the next 2.4 s. part a what is the elevator's speed 4.8 s after starting? express your answer with the appropriate units.