A ball rolls from x=-5 to x=32.4 m in 8.9 seconds. What was it’s average velocity

v = 4.20m/s

Average velocity is 4.20m/s

Explanation:

Average velocity is the change in displacement per unit time;

v = ∆x/t

Given;

∆x = 32.4 - (-5) = 37.4 m

t = 8.9 seconds

Substituting the values;

v = 37.4m/8.9s

v = 4.20m/s

Average velocity is 4.20m/s

4.157 m/s

Explanation:

Average velocity: This can be defined as the ratio change in position to time interval. The S.I unit of average velocity is m/s

The expression for average velocity is given as,

V = Δx/t Equation 1

Where V = average velocity, Δx = change in position on the x- axis, t = time.

But,

Δx = x₂-x₁ Equation 2

Substitute equation 2 into equation 1

V = (x₂-x₁)/t Equation 3

Given: x₂ = 32.4 m, x₁ = -5 m, t = 8.9 s

Substitute into equation 3

V = [32.4-(-5)]/8.9

V = (32.4+5)/8.9

V = 37.4/8.9

V = 4.157 m/s

Hence the average velocity = 4.157 m/s

Sometimes friction can be helpful. Friction can stop things that are moving from moving. For example if your pencil is rolling along the desk, friction could make it stop before it falls off.

However, friction can also be unhelpful. It can stop things from moving that should be moving. For example when playing sports, friction might slow down the ball when really you would like the ball to keep going.