In a sequence where a dot moves to the right by one unit each step, after 4 steps, where is the dot relative to the starting position?

In a sequence where a dot moves to the right by one unit each step, after 4 steps, where is the dot relative to the starting position?

• A. Two units right
• B. One unit right
• C. Four units right
• D. Three units right

Answer: (C)

Displacement adds up with each step. If the dot moves one unit to the right every step, then after four steps it has moved 1 + 1 + 1 + 1 = 4 units to the right of the start. So, relative to where it began, the dot is four units to the right. (After the first step it’s 1 unit right, after two steps 2 units right, and so on, ending at 4 units right.)

Displacement adds up with each step. If the dot moves one unit to the right every step, then after four steps it has moved 1 + 1 + 1 + 1 = 4 units to the right of the start. So, relative to where it began, the dot is four units to the right. (After the first step it’s 1 unit right, after two steps 2 units right, and so on, ending at 4 units right.)