HESI A2 PHYSICS STUDY GUIDE
1. Whenajunked car iscompacted, whichstatement istrue?
A. Itsmassincreases.
B. Itsmassdecreases.
C. Itsdensityincreases.
D. Itsdensitydecreases.
Explanation:Sincedensity =mass/volume, itshouldbeobviousthat thedecreasein volumeasacar is
crushed should lead to an increase in density. Nothing happens to change the mass of thecar.
2. A car travels 3 miles north, 6 miles south, 2 miles east, 2 miles west, and then 3
milesnorth.Which ofthe following is true?
A. Thedisplacementofthe car is16 miles,and thedistancetraveledis 0miles.
B. Thedisplacementofthe car is16 miles,and thedistancetraveledis 16miles.
C. Thedisplacement ofthecaris 0miles, and the distancetraveled is0 miles.
D. Thedisplacement ofthecaris 0miles, andthe distancetraveled is16 miles.
Expalanation: If a car travels 3 miles north, 6 miles south, 2 miles east, 2 miles west, and then
3milesnorth, ithas traveledatotal distanceof 16miles. However,becauseof thedirections
ithastraveled,it has ended upin theplacewhereit started, giving itadisplacement of0.
3. Whydoesn’ta raindropaccelerate asit approaches theground?
A. Gravitypullsitdownataconstantrate.
B. Airresistancecounteractsthegravitationalforce.
C. Itsmassdecreases,decreasingitsspeed.
D. Objectsinmotiondecelerateoverdistance.
Explanation: Gravity in fact causes acceleration, making choice A incorrect— unless
airresistancecounteractsthatacceleration,whichitmayeasilydoforanobject assmalland
, lightweightasaraindrop. Raindropsmay losemass (choiceC),but thatwould
notdecreasetheiracceleration.ChoiceDviolates Newton’sfirst law.
4. Anobject moves100 m in10 s.What is thevelocity ofthe object overthistime?
A. 10m/s
B. 90m/s
C. 110m/s
D.1,000 m/s
Explanation:Velocityis thechangeindistanceovertime.100 m/10s isthe sameas 10m/s.
5. Whichoftheseobjects hasthe greatest momentum?
A. A1,250-kg car moving at 5 m/s
B. An80-kgpersonrunningat4 m/s
C. A10-kgpieceofmeteoritemoving at600m/s
D. A0.5-kgrockmoving at40m/s
Explanation:Momentumis calculatedbymultiplying massby
velocity,p=mv.Althoughthemeteoriteseemsintimidating, itis thecar thathas
thegreatestmomentum,at6,250 kg⋅m/s.
6. Sublimation is the change in matter from solid to gas or gas to solid without
passingthroughaliquid phase.Outsideof thelaboratory, whichsolid providesthebest
exampleofthis?
A. Iron
B. Silver
C. Saltcrystal
D. Dryice
Explanation: Dry ice is frozen carbon dioxide. As it breaks down, it transforms directly into
gaswithoutpassingthroughaliquidphase.Sublimationofmetalsispossible,butnot“outsideofthelabor
atory.”
1. Whenajunked car iscompacted, whichstatement istrue?
A. Itsmassincreases.
B. Itsmassdecreases.
C. Itsdensityincreases.
D. Itsdensitydecreases.
Explanation:Sincedensity =mass/volume, itshouldbeobviousthat thedecreasein volumeasacar is
crushed should lead to an increase in density. Nothing happens to change the mass of thecar.
2. A car travels 3 miles north, 6 miles south, 2 miles east, 2 miles west, and then 3
milesnorth.Which ofthe following is true?
A. Thedisplacementofthe car is16 miles,and thedistancetraveledis 0miles.
B. Thedisplacementofthe car is16 miles,and thedistancetraveledis 16miles.
C. Thedisplacement ofthecaris 0miles, and the distancetraveled is0 miles.
D. Thedisplacement ofthecaris 0miles, andthe distancetraveled is16 miles.
Expalanation: If a car travels 3 miles north, 6 miles south, 2 miles east, 2 miles west, and then
3milesnorth, ithas traveledatotal distanceof 16miles. However,becauseof thedirections
ithastraveled,it has ended upin theplacewhereit started, giving itadisplacement of0.
3. Whydoesn’ta raindropaccelerate asit approaches theground?
A. Gravitypullsitdownataconstantrate.
B. Airresistancecounteractsthegravitationalforce.
C. Itsmassdecreases,decreasingitsspeed.
D. Objectsinmotiondecelerateoverdistance.
Explanation: Gravity in fact causes acceleration, making choice A incorrect— unless
airresistancecounteractsthatacceleration,whichitmayeasilydoforanobject assmalland
, lightweightasaraindrop. Raindropsmay losemass (choiceC),but thatwould
notdecreasetheiracceleration.ChoiceDviolates Newton’sfirst law.
4. Anobject moves100 m in10 s.What is thevelocity ofthe object overthistime?
A. 10m/s
B. 90m/s
C. 110m/s
D.1,000 m/s
Explanation:Velocityis thechangeindistanceovertime.100 m/10s isthe sameas 10m/s.
5. Whichoftheseobjects hasthe greatest momentum?
A. A1,250-kg car moving at 5 m/s
B. An80-kgpersonrunningat4 m/s
C. A10-kgpieceofmeteoritemoving at600m/s
D. A0.5-kgrockmoving at40m/s
Explanation:Momentumis calculatedbymultiplying massby
velocity,p=mv.Althoughthemeteoriteseemsintimidating, itis thecar thathas
thegreatestmomentum,at6,250 kg⋅m/s.
6. Sublimation is the change in matter from solid to gas or gas to solid without
passingthroughaliquid phase.Outsideof thelaboratory, whichsolid providesthebest
exampleofthis?
A. Iron
B. Silver
C. Saltcrystal
D. Dryice
Explanation: Dry ice is frozen carbon dioxide. As it breaks down, it transforms directly into
gaswithoutpassingthroughaliquidphase.Sublimationofmetalsispossible,butnot“outsideofthelabor
atory.”
