Một thấu kính hội tụ có tiêu cụ f=20cm tính độ tụ của thấu kính

All the simple machines make work easier to do by changing the or of a force. a. size; type b. work; type c. size; direction d. type; direction

You are given a vector a = 125i and an unknown vector b that is perpendicular to a. the cross-product of these two vectors is a × b = 98k. what is the y-component of vector b?

What is the answer to these problems 30 pt