Use the graph above to determine the change in speed of the object between 20 and 30 seconds?

6 m/s

Explanation:

To determine the change in speed of the object, we just need to determine its speed at t = 30 s and at t = 20 s, and then calculate the difference.

The speed at t = 30 is:

v = 6 m/s

While the speed at t = 20 s is:

u = 0

Therefore, the change in speed is:

Explanation:

The attached figure shows the acceleration time graph of an object. We known that the slope of the a-t graph gives the velocity of an object. The area under the a-t graph gives the velocity of object.

In x axis, time t = 30 s- 20 s = 10 s

In y axis, acceleration,

Area under the graph from 20 to 30 seconds is given by :

v = 30 m/s

So, the change in speed of the object is 30 m/s. Hence, this is the required solution.

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day