Question

question 3 (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 4 (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:

Question 3

The slope of a position - time graph is calculated as $\frac{\Delta x}{\Delta t}$. Velocity is defined as $\frac{\text{displacement}}{\text{time}}$. For an average velocity, we consider the total displacement ($\Delta x=x_f - x_i$) over the total time interval ($\Delta t=t_f - t_i$). Instantaneous velocity is the limit as $\Delta t
ightarrow0$. But the general slope (without taking the limit) of a position - time graph gives the average velocity.
Average acceleration is $\frac{\Delta v}{\Delta t}$ (related to a velocity - time graph). Distance is a scalar quantity that is not directly related to the slope (which is a vector - related quantity as it involves displacement).

Displacement is a vector quantity. Let's take the north direction as positive. The first displacement $x_1 = + 450$ m (north) and the second displacement $x_2=-200$ m (south). The total displacement $x=x_1 + x_2$.
Using the formula $x = 450-200=250$ m. Since the result is positive, the direction is north.

Answer:

C. average velocity

Question 4