Evaluate Collision Design - Middle School Physical Science
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Calculate momentum before impact: $m=2.0,kg$ and $v=3.0,m/s$.
Calculate momentum before impact: $m=2.0,kg$ and $v=3.0,m/s$.
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$p = 6.0,kg\cdot m/s$. Using $p = mv$: $2.0,kg \times 3.0,m/s = 6.0,kg\cdot m/s$.
$p = 6.0,kg\cdot m/s$. Using $p = mv$: $2.0,kg \times 3.0,m/s = 6.0,kg\cdot m/s$.
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Identify which design best satisfies a mass constraint: limit $\le 50,g$; Design A $45,g$, Design B $55,g$.
Identify which design best satisfies a mass constraint: limit $\le 50,g$; Design A $45,g$, Design B $55,g$.
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Design A. $45,g < 50,g$ meets the constraint; $55,g > 50,g$ exceeds it.
Design A. $45,g < 50,g$ meets the constraint; $55,g > 50,g$ exceeds it.
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Choose the safer design if $\Delta p$ is the same: Design A $\Delta t=0.10,s$ or Design B $\Delta t=0.25,s$.
Choose the safer design if $\Delta p$ is the same: Design A $\Delta t=0.10,s$ or Design B $\Delta t=0.25,s$.
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Design B. Longer time ($0.25,s > 0.10,s$) means lower force for same impulse.
Design B. Longer time ($0.25,s > 0.10,s$) means lower force for same impulse.
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Which metric most directly indicates passenger safety in a crash: peak force or total momentum?
Which metric most directly indicates passenger safety in a crash: peak force or total momentum?
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Peak force. Lower peak forces reduce injury risk more than total momentum does.
Peak force. Lower peak forces reduce injury risk more than total momentum does.
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What is the momentum formula used to evaluate how a design changes an object's motion?
What is the momentum formula used to evaluate how a design changes an object's motion?
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$p = mv$. Momentum equals mass times velocity, measuring an object's motion quantity.
$p = mv$. Momentum equals mass times velocity, measuring an object's motion quantity.
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What is the kinetic energy formula used to compare how much energy a design must absorb?
What is the kinetic energy formula used to compare how much energy a design must absorb?
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$KE = \frac{1}{2}mv^2$. Kinetic energy equals half the mass times velocity squared.
$KE = \frac{1}{2}mv^2$. Kinetic energy equals half the mass times velocity squared.
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What is a criterion in an engineering collision-design evaluation?
What is a criterion in an engineering collision-design evaluation?
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A required performance goal the design should meet. Criteria are specific goals the design must achieve to be successful.
A required performance goal the design should meet. Criteria are specific goals the design must achieve to be successful.
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What is a constraint in an engineering collision-design evaluation?
What is a constraint in an engineering collision-design evaluation?
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A limit on materials, size, mass, time, or cost. Constraints restrict what resources or parameters can be used in the design.
A limit on materials, size, mass, time, or cost. Constraints restrict what resources or parameters can be used in the design.
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What design feature most directly reduces peak force by increasing collision time?
What design feature most directly reduces peak force by increasing collision time?
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Crumple zone (energy-absorbing deformation). Crumple zones extend collision time by deforming, reducing peak forces.
Crumple zone (energy-absorbing deformation). Crumple zones extend collision time by deforming, reducing peak forces.
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Identify the collision type that best reduces rebound and usually helps lower injury risk.
Identify the collision type that best reduces rebound and usually helps lower injury risk.
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Inelastic collision. Objects stick together or deform permanently, minimizing dangerous rebounds.
Inelastic collision. Objects stick together or deform permanently, minimizing dangerous rebounds.
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What does a free-body diagram show that helps evaluate forces during a collision?
What does a free-body diagram show that helps evaluate forces during a collision?
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All forces acting on an object during the collision. Arrows represent all forces' magnitudes and directions on the object.
All forces acting on an object during the collision. Arrows represent all forces' magnitudes and directions on the object.
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Which option is the best evidence that a collision design met a force-limit criterion?
Which option is the best evidence that a collision design met a force-limit criterion?
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Measured peak force is below the specified maximum. Direct measurement confirms the design stays within the force limit.
Measured peak force is below the specified maximum. Direct measurement confirms the design stays within the force limit.
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Identify whether the design meets the criterion: max force $\le 800,N$; test peak force $=750,N$.
Identify whether the design meets the criterion: max force $\le 800,N$; test peak force $=750,N$.
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Meets the criterion. $750,N < 800,N$, so the force stays below the maximum allowed.
Meets the criterion. $750,N < 800,N$, so the force stays below the maximum allowed.
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Identify whether the design meets the criterion: stopping time $\ge 0.20,s$; test time $=0.15,s$.
Identify whether the design meets the criterion: stopping time $\ge 0.20,s$; test time $=0.15,s$.
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Does not meet the criterion. $0.15,s < 0.20,s$, so the time is too short to meet the requirement.
Does not meet the criterion. $0.15,s < 0.20,s$, so the time is too short to meet the requirement.
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Identify the best choice if the criterion is minimum rebound speed after impact: lower or higher rebound speed?
Identify the best choice if the criterion is minimum rebound speed after impact: lower or higher rebound speed?
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Lower rebound speed. Lower rebound means less energy returned, meeting safety goals.
Lower rebound speed. Lower rebound means less energy returned, meeting safety goals.
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Which option is a valid controlled variable when testing collision designs: drop height or padding thickness?
Which option is a valid controlled variable when testing collision designs: drop height or padding thickness?
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Drop height (keep it constant to compare designs fairly). Controlled variables must stay constant; padding varies between designs.
Drop height (keep it constant to compare designs fairly). Controlled variables must stay constant; padding varies between designs.
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Choose the correct conclusion if results vary widely across trials for the same design.
Choose the correct conclusion if results vary widely across trials for the same design.
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Reliability is low; more trials or better control is needed. High variability indicates poor experimental control or repeatability.
Reliability is low; more trials or better control is needed. High variability indicates poor experimental control or repeatability.
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What is the definition of a perfectly inelastic collision in design evaluation?
What is the definition of a perfectly inelastic collision in design evaluation?
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Objects stick together after impact and move as one. Maximum kinetic energy loss occurs when objects combine.
Objects stick together after impact and move as one. Maximum kinetic energy loss occurs when objects combine.
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What is the definition of an inelastic collision used in evaluating designs?
What is the definition of an inelastic collision used in evaluating designs?
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A collision in which kinetic energy is not conserved. Some kinetic energy converts to heat, sound, or deformation.
A collision in which kinetic energy is not conserved. Some kinetic energy converts to heat, sound, or deformation.
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What is the definition of an elastic collision used in evaluating designs?
What is the definition of an elastic collision used in evaluating designs?
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A collision in which kinetic energy is conserved. Total kinetic energy before equals total kinetic energy after.
A collision in which kinetic energy is conserved. Total kinetic energy before equals total kinetic energy after.
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What does it mean if a prototype meets all criteria but violates one constraint?
What does it mean if a prototype meets all criteria but violates one constraint?
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It is not acceptable; constraints must also be satisfied. Both criteria and constraints must be met for success.
It is not acceptable; constraints must also be satisfied. Both criteria and constraints must be met for success.
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Which quantity is most directly reduced by adding padding or crumple zones to a design?
Which quantity is most directly reduced by adding padding or crumple zones to a design?
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Average impact force, $F$. Padding extends collision time, directly reducing average force.
Average impact force, $F$. Padding extends collision time, directly reducing average force.
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What key change reduces peak force in a collision design when momentum change is fixed?
What key change reduces peak force in a collision design when momentum change is fixed?
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Increase the collision time, $\Delta t$. Longer collision time spreads the same impulse, reducing peak force.
Increase the collision time, $\Delta t$. Longer collision time spreads the same impulse, reducing peak force.
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What formula relates momentum to mass and velocity for evaluating collisions?
What formula relates momentum to mass and velocity for evaluating collisions?
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$p = mv$. Momentum is the product of an object's mass and velocity.
$p = mv$. Momentum is the product of an object's mass and velocity.
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What is the impulse-momentum relationship used to evaluate collision designs?
What is the impulse-momentum relationship used to evaluate collision designs?
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$J = F\Delta t = \Delta p$. Impulse equals force times time, which equals momentum change.
$J = F\Delta t = \Delta p$. Impulse equals force times time, which equals momentum change.
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