Question

On a 100m straight track, Zak runs to the 80m mark in 15s. He then runs back to the 20m in 10s. He then runs to the 100m mark in 20s. Finally he runs to the 70m mark in 5s. The total distance travelled by Zak is ____ m and total displacement is ____ m.

Answer 1

Answer:

The total distance traveled by Zak is 250 m and total displacement is

70 m

Explanation:

Distance is a scalar quantity that represents how much ground an

object has covered during its motion

Displacement is a vector quantity that represents how far out of place

an object is, means the change in its position

Displacement = final position - initial position

The straight track is 100 m

Zak runs to the 80 m mark

That means he runs forward from zero to 80

Then his distance = 80 m

His displacement = + 80 m

He then runs back to the 20 m

That means that he runs back from 80 m to 20 m

Then his distance = 80 - 20 = 60 m

His displacement = 20 - 80 = -60 m

He then runs to the 100 m mark

That means he runs forward from 20 m to 100 m

Then his distance = 100 - 20 = 80 m

His displacement = 100 - 20 = + 80 m

Finally he runs to the 70 m mark

That means he runs back from 100 m to 70 m

Then his distance = 100 - 70 = 30 m

His displacement = 70 - 100 = - 30 m

His total distance is the sum of all distances he runs

The total distance = 80 + 60 + 80 + 30 = 250 m

His total displacements is the sum of all displacements he runs

The total displacement = (+80) + (-60) + (+80) + (-30) = + 70 m

The total distance traveled by Zak is 250 m and total displacement is

70 m