Question

question 21 (1 point)
the slope of a position–time graph measures which of the following quantities?
(a) average acceleration
(b) instantaneous velocity
(c) average velocity
(d) distance

a

b

c

d
question 22 (1 point)
if you walk 450 m north and then 200 m south, what is your displacement?
(a) 250 m
(b) 250 m north
(c) 650 m
(d) 650 m north

a

b

c

d

Explanation:

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Question 21

A position-time graph's slope at a point is the ratio of instantaneous change in position to instantaneous change in time, which defines instantaneous velocity. Average velocity uses total displacement over total time (a secant slope), acceleration is slope of velocity-time graphs, and distance is total path length unrelated to this slope.

Step1: Define direction convention

Let north = positive, south = negative.

Step2: Calculate total displacement

Displacement: $450\ \text{m} + (-200\ \text{m}) = 250\ \text{m}$
Positive value means direction is north.

Answer:

(b) instantaneous velocity

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Question 22