Aweb page designer creates an animation in which a dot on a computer screen has a position of r⃗ =[ 4.2 cm +( 2.5 cm/s2 )t2]i^+( 5.5 cm/s )tj^ .find the average velocity of the dot between t=0 and t=2.0s. give your answer as a pair of components separated by a comma. for example, if you think the x component is 3 and the y component is 4, then you should enter 3,4. express your answer using two significant figures.