Mechanics midterm-terminal velocity question

In summary, the conversation discusses the calculation of terminal velocity for a boy sliding on a water sliding bed at an angle θ with the horizontal. The formula for terminal velocity takes into account the coefficients of kinetic friction (μ) and water resistance (F(v)=-cv) as well as the force due to gravity (F) and the downhill component of the gravitational force (mgsin(θ)). The conversation also addresses the integration of this formula to find the terminal velocity, which will have an exponential term that decreases over time.
  • #1
Kara-Mustafa
1
0
1. A boy is sliding on the water sliding bed. The angle between sliding bed and the horizontal is θ(theta). When the coefficient of the kinetic friction is μ(COF) and when the wate resistance is F(v)=-cv, obtain the terminal velocity. (two frictions - for this i don't know whether it means linear friction+quadratic friction or something else)



3. But anyway, so far I reached this point:

F-force due to gravity
F(v) - force due to water resistance

F*μ+F(v)=mdv/dt

-mgsin(θ)μ-cv=mdv/dt

dt=mdv/mgsin(θ)μ -cv

And I'm stuck right here. Are my workings so far correct? Can you show me how to integrate this function and find terminal velocity. I know it's going to have exponential term which will drop to zero after sufficient time.
 
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  • #2
Welcome to PF!

Hi Kara-Mustafa!Welcome to PF! :smile:

You're confusing the friction (µN) with the downhill component of the gravitational force …

you need both :wink:
 

Related to Mechanics midterm-terminal velocity question

1. What is terminal velocity in mechanics?

Terminal velocity is the constant maximum speed that an object falling through a fluid, such as air, can reach. It occurs when the force of gravity pulling the object downward is equal to the force of air resistance pushing upward.

2. How is terminal velocity calculated?

The formula for terminal velocity is Vt = √(2mg/ρAC), where Vt is the terminal velocity, m is the mass of the falling object, g is the acceleration due to gravity, ρ is the density of the fluid, A is the cross-sectional area of the object, and C is the drag coefficient.

3. How does air resistance affect terminal velocity?

Air resistance, also known as drag force, increases as the velocity of a falling object increases. As the drag force increases, it eventually becomes equal to the force of gravity, resulting in a constant terminal velocity. This means that the object will continue to fall at the same speed until it reaches the ground.

4. Can an object reach a terminal velocity in a vacuum?

No, an object cannot reach terminal velocity in a vacuum as there is no fluid present to create air resistance. In a vacuum, an object will continue to accelerate due to the force of gravity until it reaches the ground or another object.

5. What factors affect terminal velocity?

The factors that affect terminal velocity include the mass and shape of the falling object, the density and viscosity of the fluid, and the gravitational acceleration. Additionally, any external forces acting on the object, such as wind or air currents, can also affect terminal velocity.

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