Laura takes her little brother for a walk in the park from the benches to the water fountain. Laura walks in a straight line while her brother runs in circles around her. They both take the same number of seconds to reach the water fountain. Which of these is true? [Hint: distance and speed are scalars, displacement and velocity are vectors] * 1 point Laura and her brother traveled the same distance. Laura’s brother had a greater displacement than Laura. Laura’s brother had a greater average velocity than Laura. Laura and her brother had the same average velocity.

answer: - first one is the correct answer. .

explanations: - potassium sulfide is and cobalt(ii) chloride is .

charge on k is +1, charge on s is -2, charge on co is +2 and charge on cl is -1.

in a double replacement reaction the ion exchange takes place. in general the reaction looks like:

if one of the product is insoluble as per solubility rules then a precipitate of it is formed.

when we mix the aqueous solutions of potassium sulfide and cobalt(ii) chloride then chloride ion goes with potassium ion and sulfide ion goes with cobalt ion and the balanced equation is written as:

k and cl has equal charges, similarly co and s has equal charges and hence no subscripts are used for the product side.

as per the solubility rules, cos is insoluble and so it's precipitate is formed.

looking at the given choices, first choice is correct.