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Physics

2 answers:

erastova [34]3 years ago

8 0

The formula your looking for is Vf = Vi + A (T)

Vf = Velocity Final
Vi = Velocity Initial
A = Acceleration
T = Time

Our Initial Velocity is 15m/s. That’s our starting point.

Acceleration is -3m/s. It’s negative because we’re slowing down

We know that the cyclist comes to a complete stop, which means the Final Velocity is 0

In order to solve this with the equation. We need three of the four variables. We just don’t know time. So our setup is -

0 = 15-3(T)

Then you solve

NeTakaya3 years ago

4 0

Answer:hi

Explanation:

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When visiting some countries, you may see a person balancing a load on the head. Explain why the center of mass of the load need

Vinvika [58]

Explanation:

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3 0

3 years ago

The height of a typical playground slide is about 1.8 m and it rises at an angle of 30 ∘ above the horizontal.

Salsk061 [2.6K]

Answer:

$5.94\ \text{m/s}$

$1.7$

$0.577$

Explanation:

g = Acceleration due to gravity = $9.81\ \text{m/s}^2$

$\theta$ = Angle of slope = $30^{\circ}$

v = Velocity of child at the bottom of the slide

$\mu_k$ = Coefficient of kinetic friction

$\mu_s$ = Coefficient of static friction

h = Height of slope = 1.8 m

The energy balance of the system is given by

$mgh=\dfrac{1}{2}mv^2\\\Rightarrow v=\sqrt{2gh}\\\Rightarrow v=\sqrt{2\times 9.81\times 1.8}\\\Rightarrow v=5.94\ \text{m/s}$

The speed of the child at the bottom of the slide is $5.94\ \text{m/s}$

Length of the slide is given by

$l=h\sin\theta\\\Rightarrow l=1.8\sin30^{\circ}\\\Rightarrow l=0.9\ \text{m}$

$v=\dfrac{1}{2}\times5.94\\\Rightarrow v=2.97\ \text{m/s}$

The force energy balance of the system is given by

$mgh=\dfrac{1}{2}mv^2+\mu_kmg\cos\theta l\\\Rightarrow \mu_k=\dfrac{gh-\dfrac{1}{2}v^2}{gl\cos\theta}\\\Rightarrow \mu_k=\dfrac{9.81\times 1.8-\dfrac{1}{2}\times 2.97^2}{9.81\times 0.9\cos30^{\circ}}\\\Rightarrow \mu_k=1.73$