Physics 250 Final Exam Theory Questions with correct answers

Physics 250 Final Exam Theory Questions
| | | | | |




with correct answers
| |




You |need |to |load |a |crate |of |mass |m |onto |the |bed |of |a |truck. |One |possibility |is |just |to |lift |the |crate |
straight |up |over |a |height |h, |equal |to |height |of |the |truck's |bed. |The |force |exert |in |this |case |is |F1 |and |
the |work |one |in |this |case |is |W1. |The |other |possibility |is |to |slight |the |crate |up |a |frictional |ramp |of |
length |L. |In |this |case, |you |exert |force |F2 |and |perform |work |W2. |Which |statement |is |true?

A. |F1>F2 |and |W1>W2

B. |F1=F2 |and |W1>W2

C. |F1=F2 |and |W1=W2

D. |F1>F2 |and |W1<W2

E. |F1>F2 |and |W1=W2 |- |✔✔E



Identical |forces |act |for |the |same |length |of |time |on |two |different |masses. |The |change |in |momentum |
of |the |smaller |mass |is:

A. |Equal |to |the |change |in |momentum |of |the |larger |mass

B. |Larger |than |the |change |in |momentum |of |the |larger |mass

C. |Smaller |than |the |change |in |momentum |of |the |larger |mass, |but |not |zero |kg |m/s

D. |Cannot |tell |without |knowing |masses

E. |Zero |kg |m/s |- |✔✔A



An |inelastic |collision |between |two |objects |is |characterized |by |the |following:

A. |Total |momentum |of |the |system |is |conserved

B. |Total |energy |of |the |system |is |conserved

C. |Total |kinetic |energy |of |the |system |remains |constant

D. |Both |A |and |B |are |true

E. |Both |A |and |C |are |true |- |✔✔A

, You |throw |a |rudder |ball |at |a |downward |angle |so |that |when |it |hits |the |ground, |the |ball |bounces |off |
with |the |same |speed |with |which |it |hit |the |ground. |How |could |you |increase |the |impulse |the |ground |
exerts |on |the |ball |by |the |collision |(assume |you |always |throw |the |ball |at |the |same |initial |speed)?

A. |Since |the |ball's |speed |does |not |change |as |a |result |of |the |collision, |the |impulse |exerted |on |it |by |the
|ground |is |the |same |regardless |of |how |it |is |thrown



B. |By |throwing |the |ball |at |a |steeper |angle |(i.e. |so |its |initial |velocity |is |closer |to |being |directly |down)

C. |Since |the |ball's |speed |does |not |change |as |a |result |of |the |collision, |the |impulse |exerted |on |it |by |the
|ground |is |always |0Ns



D. |By |throwing |the |ball |at |a |shallower |angle |(i.e. |so |its |initial |velocity |is |farther |from |being |directly |
down)

E. |By |throwing |the |ball |at |the |same |angle |with |respect |to |the |vertical |but |directed |above |the |
horizontal |- |✔✔B



Two |boxes |of |mass |m |and |M |are |stacked |on |the |floor |of |an |elevator |(m |stacked |on |top |of |M). |If |the |
elevator |is |accelerating |down |with |magnitude |a, |what |is |the |magnitude |of |the |force |exerted |on |block |
m |by |block |M?

A. |m |(g-a)

B. |(m+M) |(g+a)

C. |M |(g-a)

D. |m |(g+a)

E. |(m+M) |(g-a) |- |✔✔A



A |2 |kg |object |is |falling |downward |with |its |speed |increasing |at |a |rate |of |8 |m/s/s. |We |conjecture |that |
there |must |be |some |other |force |acting |on |the |object |in |addition |to |the |downward |pull |of |gravity. |
What |can |we |say |about |the |other |force?

A. |It |has |a |magnitude |of |4N |and |points |in |the |upward |direction

B. |It |has |a |magnitude |of |36N |and |points |in |the |upward |direction

C. |It |has |a |magnitude |of |20N |and |points |in |the |downward |direction

D. |It |has |a |magnitude |of |16N |and |points |in |the |upward |direction

E. |It |has |a |magnitude |of |2N |and |points |in |the |downward |direction |- |✔✔A



When |a |projectile |is |fired |horizontally |at |a |speed |v |from |a |height |d |above |the |surface |of |a |table, |it |
travels |a |distance |of |L |horizontally |before |it |hits |the |table. |Next, |the |same |projectile |is |fired |