Is velocity a scalar or a vector

Current enters a circuit at a: 1.positive terminal 2.negative terminal 3.low potential side 4.resistor

Calculate the mass of an object that has a momentum of 100kg x m/sec and velocity of 4 m/sec

The position of a crate sliding down a ramp is given by x=(0.05t^3) m, y=(1.7t^2) m, z=(6−0.85t^5/2) m, where t is in seconds. (a) determine the magnitude of the crate's velocity when t = 2 s. (b) determine the magnitude of the crate's acceleration when t = 2 s.