Resistive Forces - AP Physics C: Mechanics
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What is the primary cause of resistive forces in fluids?
What is the primary cause of resistive forces in fluids?
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Viscosity and drag. Internal friction in fluids creates resistance to relative motion.
Viscosity and drag. Internal friction in fluids creates resistance to relative motion.
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Identify the resistive force when an object slides along a surface.
Identify the resistive force when an object slides along a surface.
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Frictional force. Surface contact force opposing sliding motion between solid objects.
Frictional force. Surface contact force opposing sliding motion between solid objects.
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What does the symbol $\text{μ}$ represent in the frictional force formula?
What does the symbol $\text{μ}$ represent in the frictional force formula?
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The coefficient of friction. Dimensionless constant depending on surface materials and conditions.
The coefficient of friction. Dimensionless constant depending on surface materials and conditions.
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Identify the two types of frictional forces.
Identify the two types of frictional forces.
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Static friction and kinetic friction. Static prevents motion initiation, kinetic acts during sliding.
Static friction and kinetic friction. Static prevents motion initiation, kinetic acts during sliding.
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State the difference between static and kinetic friction.
State the difference between static and kinetic friction.
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Static friction acts when motion hasn't started, kinetic during motion. Static friction prevents motion, kinetic acts during ongoing motion.
Static friction acts when motion hasn't started, kinetic during motion. Static friction prevents motion, kinetic acts during ongoing motion.
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Which type of friction generally has a higher coefficient, static or kinetic?
Which type of friction generally has a higher coefficient, static or kinetic?
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Static friction. Static friction is typically stronger than kinetic friction.
Static friction. Static friction is typically stronger than kinetic friction.
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State the difference between static and kinetic friction.
State the difference between static and kinetic friction.
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Static friction acts when motion hasn't started, kinetic during motion. Static friction prevents motion, kinetic acts during ongoing motion.
Static friction acts when motion hasn't started, kinetic during motion. Static friction prevents motion, kinetic acts during ongoing motion.
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What is the net force if $F_{\text{applied}} = 10 \text{ N}$ and $f = 5 \text{ N}$?
What is the net force if $F_{\text{applied}} = 10 \text{ N}$ and $f = 5 \text{ N}$?
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$F_{\text{net}} = 5 \text{ N}$. Applied force minus opposing friction gives net force.
$F_{\text{net}} = 5 \text{ N}$. Applied force minus opposing friction gives net force.
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State the effect of increased velocity on fluid resistive force.
State the effect of increased velocity on fluid resistive force.
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Increases resistive force. Higher speeds create proportionally greater fluid resistance.
Increases resistive force. Higher speeds create proportionally greater fluid resistance.
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What is the formula for terminal velocity in terms of $b$, $m$, and $g$?
What is the formula for terminal velocity in terms of $b$, $m$, and $g$?
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$v_t = \frac{mg}{b}$. Weight divided by drag coefficient gives terminal velocity.
$v_t = \frac{mg}{b}$. Weight divided by drag coefficient gives terminal velocity.
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Calculate $v_t$ for $m = 5 \text{ kg}$, $g = 9.8 \text{ m/s}^2$, $b = 0.4$.
Calculate $v_t$ for $m = 5 \text{ kg}$, $g = 9.8 \text{ m/s}^2$, $b = 0.4$.
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$v_t = 122.5 \text{ m/s}$. Using $v_t = \frac{mg}{b} = \frac{5 \times 9.8}{0.4} = 122.5$ m/s.
$v_t = 122.5 \text{ m/s}$. Using $v_t = \frac{mg}{b} = \frac{5 \times 9.8}{0.4} = 122.5$ m/s.
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Identify the resistive force opposing an object sliding down an incline.
Identify the resistive force opposing an object sliding down an incline.
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Frictional force. Surface contact creates sliding resistance on inclined planes.
Frictional force. Surface contact creates sliding resistance on inclined planes.
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Identify the resistive force acting on an object moving through a fluid.
Identify the resistive force acting on an object moving through a fluid.
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Drag force. Force opposing motion when objects move through fluids like air or water.
Drag force. Force opposing motion when objects move through fluids like air or water.
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Find the resistive force on an object with $v = 5 \text{ m/s}$ and $b = 0.2$ in low-speed.
Find the resistive force on an object with $v = 5 \text{ m/s}$ and $b = 0.2$ in low-speed.
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$F_{\text{drag}} = -1 \text{ N}$. Using $F = -bv = -0.2 \times 5 = -1$ N.
$F_{\text{drag}} = -1 \text{ N}$. Using $F = -bv = -0.2 \times 5 = -1$ N.
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Which force counteracts forward motion in a vehicle?
Which force counteracts forward motion in a vehicle?
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Air resistance. Atmospheric resistance opposes vehicle forward motion.
Air resistance. Atmospheric resistance opposes vehicle forward motion.
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Find the resistive force on an object with $v = 3 \text{ m/s}$ and $b = 0.1$ in high-speed.
Find the resistive force on an object with $v = 3 \text{ m/s}$ and $b = 0.1$ in high-speed.
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$F_{\text{drag}} = -0.9 \text{ N}$. Using $F = -bv^2 = -0.1 \times 3^2 = -0.9$ N.
$F_{\text{drag}} = -0.9 \text{ N}$. Using $F = -bv^2 = -0.1 \times 3^2 = -0.9$ N.
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State the expression for terminal velocity in terms of $mg$ and $b$.
State the expression for terminal velocity in terms of $mg$ and $b$.
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$v_t = \frac{mg}{b}$. When drag force equals weight, acceleration becomes zero.
$v_t = \frac{mg}{b}$. When drag force equals weight, acceleration becomes zero.
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At terminal velocity, what is the net force on the object?
At terminal velocity, what is the net force on the object?
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Zero. Balanced forces result in constant velocity motion.
Zero. Balanced forces result in constant velocity motion.
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Which force opposes the motion of a bicycle moving through air?
Which force opposes the motion of a bicycle moving through air?
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Air resistance. Atmospheric drag opposes forward bicycle motion.
Air resistance. Atmospheric drag opposes forward bicycle motion.
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State the relationship between resistive force and velocity in high-speed conditions.
State the relationship between resistive force and velocity in high-speed conditions.
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Quadratic relationship. Drag force increases with velocity squared at high speeds.
Quadratic relationship. Drag force increases with velocity squared at high speeds.
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Calculate the drag force for $v = 4 \text{ m/s}$ and $b = 0.3$ in low-speed.
Calculate the drag force for $v = 4 \text{ m/s}$ and $b = 0.3$ in low-speed.
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$F_{\text{drag}} = -1.2 \text{ N}$. Using $F = -bv = -0.3 \times 4 = -1.2$ N.
$F_{\text{drag}} = -1.2 \text{ N}$. Using $F = -bv = -0.3 \times 4 = -1.2$ N.
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Find the normal force if $m = 10 \text{ kg}$ and $g = 9.8 \text{ m/s}^2$ on a flat surface.
Find the normal force if $m = 10 \text{ kg}$ and $g = 9.8 \text{ m/s}^2$ on a flat surface.
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$N = 98 \text{ N}$. Weight equals normal force on horizontal surface.
$N = 98 \text{ N}$. Weight equals normal force on horizontal surface.
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What is the effect of increasing surface roughness on friction?
What is the effect of increasing surface roughness on friction?
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Increases friction. Rougher surfaces have higher friction coefficients.
Increases friction. Rougher surfaces have higher friction coefficients.
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Identify the resistive force in a viscous liquid.
Identify the resistive force in a viscous liquid.
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Viscous drag. Thick liquids create velocity-dependent resistance.
Viscous drag. Thick liquids create velocity-dependent resistance.
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What occurs to resistive forces when an object reaches terminal velocity?
What occurs to resistive forces when an object reaches terminal velocity?
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They equal the gravitational force. Force balance occurs when drag matches gravitational force.
They equal the gravitational force. Force balance occurs when drag matches gravitational force.
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Identify the resistive force when an object slides along a surface.
Identify the resistive force when an object slides along a surface.
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Frictional force. Surface contact force opposing sliding motion between solid objects.
Frictional force. Surface contact force opposing sliding motion between solid objects.
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Identify the resistive force in a viscous liquid.
Identify the resistive force in a viscous liquid.
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Viscous drag. Thick liquids create velocity-dependent resistance.
Viscous drag. Thick liquids create velocity-dependent resistance.
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Which force counteracts forward motion in a vehicle?
Which force counteracts forward motion in a vehicle?
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Air resistance. Atmospheric resistance opposes vehicle forward motion.
Air resistance. Atmospheric resistance opposes vehicle forward motion.
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What is the formula for resistive force due to air resistance in low-speed conditions?
What is the formula for resistive force due to air resistance in low-speed conditions?
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$F_{\text{drag}} = -bv$. Linear relationship for low speeds where drag is proportional to velocity.
$F_{\text{drag}} = -bv$. Linear relationship for low speeds where drag is proportional to velocity.
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What is the formula for resistive force due to air resistance in high-speed conditions?
What is the formula for resistive force due to air resistance in high-speed conditions?
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$F_{\text{drag}} = -bv^2$. Quadratic relationship for high speeds where drag is proportional to velocity squared.
$F_{\text{drag}} = -bv^2$. Quadratic relationship for high speeds where drag is proportional to velocity squared.
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