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# A sphere is rolled down in smooth slope .if the sphere has move 20 meters after 10 second calculate it final speed v?

### 3 Answers

- Wayne DeguManLv 74 weeks ago
We can apply kinematics here using s = ut + (1/2)at²

With u = 0, t = 10 and s = 20 we get:

20 = (1/2)a(10)²

so, a = 0.4 ms⁻²

Then, applying v² = u² + 2as we have:

v² = 2(0.4)(20)

so, v² = 16

Hence, v = 4 ms⁻¹

:)>

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- NCSLv 71 month ago
I guess we have to assume that the sphere starts from rest, and its final speed is reached after 20 meters.

final V = 2*Vavg = 2*20m / 10s = 4 m/s ◄

Now if the slope is longer than 20 meters, then:

(i) find the acceleration

a = 4m/s / 10s = 0.4 m/s²

and then at the bottom of the slope

final v = √(2*a*d) = √(2 * 0.4m/s² * d) = √(0.8m/s² * d)

so, for instance, if your slope was 30 m,

final v ≈ 5 m/s

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- FiremanLv 71 month ago
By s = ut + 1/2at^2

=>20 = 0 + 1/2 x a x (10)^2

=>a = 0.40 m/s^2

Thus by v = u + at

=>v = 0 + 0.40 x 10

=>v = 4 m/s

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