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PHYSICS COURSE (AIEEE/PET/PMT-2013) SARASWATI EDUCATIONAL INSTITUTE WORK -1 December 8, 2014 w -1

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600100 N

10kg

10kg

. A body of mass m is moving in a circle of radius r wit a constant s!eed v" # e force on t e body is

r mv 2

and is directed towards t e centre" $ at is t ework done by t is force in moving t e body over alf t e circumference of t e circle [NCERT 1977]

%a& 2

2

r mv %b&'ero %c& 2

2

r mv

%d& 22

mv r

. A man !us es a wall and fails to dis!lace it" (e does[CPMT 1992]%a& Negative work %b& )ositive but not ma*imum work %c& No work at all%d& +a*imum work

. A body moves a distance of 10 m along a straig tline under t e action of a force of N " -f t e work done is 2 joules , t e angle w ic t e force makeswit t e direction of motion of t e body is%a& 0.%b&/0.%c& 60.%d& 0.

. ou lift a eavy book from t e floor of t e room and kee! it in t e book s elf aving a eig t 2 m" -n t is !rocess you take seconds"# e work done by you will de!end u!on [MP PET 1993]

%a& +ass of t e book and time taken%b& $eig t of t e book and eig t of t e book s elf %c& (eig t of t e book s elf and time taken

%d& +ass of t e book, eig t of t e book s elf and time taken

. A body of mass m kg is lifted by a man to a eig t of one metre in /0 sec " Anot er man lifts t e samemass to t e same eig t in 60 sec" # e work done byt em are in t e ratio [MP PMT 1993]

%a& 2:1 %b&1 3 1%c& 2 3 1%d& 4 3 1. A body of mass 10 kg is dro!!ed to t e ground from

a eig t of 10 metres " # e work done by t e

gravitational force is )sec/!"(2mg =

[SCRA 1994]

%a& 4 0 J %b&5 4 0 J %c& 80 J %d& 5 80 J . A body of mass kg is !laced at t e origin, and can

move only on t e * a*is" A force of 10 N is acting onit in a direction making an angle of o#0 wit t e *a*is and dis!laces it along t e * a*is by 4 metres "

# e work done by t e force is [MP PET 2003]%a& 2" J %b& "2 J %c& 40 J %d& 20 J

. A 0 kg man wit 20 kg load on is ead climbs u! 20ste!s of 0"2 m eig t eac " # e work done inclimbing is [JIPMER 2002]%a& J %b&/ 0 J %c& 100 J %d& /4/0 J

. A !article is acted u!on by a force of constantmagnitude w ic is always !er!endicular to t evelocity of t e !article, t e motion of t e !articletakes !lace in a !lane" -t follows t at [AIEEE 2004]

%a& -ts velocity is constant %b& -ts acceleration is cons%c&-ts kinetic energy is constant%d&-t moves in a straig t line

10. A cord is used to lower vertically a block of mass by a distance d wit constant downward acceleration

$g

" $ork done by t e cord on t e block is [CPMT 1972

%a& $d

Mg%b& $

3 d

Mg%c& $

3 dMg%d& Mgd

11. A body moves a distance of 10 m along a straig

line under t e action of a force of N " -f t e wodone is 0 joules , t e angle w ic t e force makeswit t e direction of motion of t e body is [NCERT 198JIPMER 1997; CBSE PMT 1999;BHU 2000; RPMT 2000; Or !!" JEE

%a& 0.%b&/0.%c& 60.%d&12. A body of mass 10 kg is dro!!ed to t e ground from

a eig t of 20 metres " # e work done by t e

gravitational force is )sec/!"(2mg =

[SCRA 1994]

%a& 2k7%b&5 2k7%c& 1k7%d& 5

13.A body of mass kg is !laced at t e origin, and canmove only on t e * a*is" A force of 10 N is acting it in a direction making an angle of o#0 wit t e *a*is and dis!laces it along t e * a*is by 10 metr# e work done by t e force is [MP PET 2003]%a& 2" J %b& "2 J %c& 0 J %d& 100 J

14. A cord is used to lower vertically a block of mass by a distance d wit constant downward acceleration

$g

" $ork done by t e gravitational force on t e

block is [CPMT 1972]

%a& $d

Mg%b& $

3 d

Mg%c& $

3 dMg%d& Mgd

15. in given figure ob7ect moved at a distance 10 m "t en work done is

%a& 007 %b&1007 %c&10007 %d&10716. iven figure ob7ect moved at a distance 10 m and

a!!lied force 100N and coefficient of friction is 0"t en work done by t e friction force is

%a& 007 %b&5 007 %c&10007 %d&

17. iven figure ob7ect moved at a distance 10 m anda!!lied force 100N and coefficient of friction is 0"t en total work done

%a& 007 %b&5 007 %c&10007 %d&107

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2kg10m/00

2kg

10m

/00

10kg

v)

9

(A

D

: ;

8. A uniform c ain of lengt / m is ke!t on a table suc t at alengt of 60 cm angs freely from t e edge of t e table" # etotal mass of t e c ain is 4 kg. $ at is t e work done in

!ulling t e entire c ain on t e table %a& "2 J %b&/"6 J %c& 120 J %d& 1200 J

9. A uniform c ain of lengt L and mass M is lying on asmoot table and one t ird of its lengt is anging verticallydown over t e edge of t e table" -f g is acceleration due togravity, t e work re?uired to !ull t e anging !art on to t etable is