Init. A almatien
Quiz 1
As shown in the figure below, Justin walks from the house to his truck on a windy day. He walks 20 m
toward the truck, 15 m back to retrieve his wind-blown hat, and another 20 m to reach the truck. He
walked a total time of 75 s.
20 m
15 m
20 m
What is Justin's average velocity over the 75 s period?

v = 1/3 m / s = 0.333 m / s

in the direction of the truck

Explanation:

The average speed is defined by the variation of the position between the time spent

           v = Δx / Δt

since the position is a vector we must add using vectors, we will assume that the displacement to the right is positive, the total displacement is

           Δx = 20 - 15 +20

           Δx = 25 m

therefore we calculate

         v = 25/75

         v = 1/3 m / s = 0.333 m / s

in the direction of the truck

we need to know the time interval during which the force acts. impulse of force = momentum change