1 ) A force of 50 N is acted on a body of mass 5
kg which is at rest , for an interval of 3 secs , then impulse is : -
A ) 100 N / sec , B
) 120 N / sec ,
C ) 150 N / sec , D
) None of these ,
Correct Answer :
-
Solution : -
I = f x t ,
I = 50 x 3 = 150 N / sec .
2 ) The resultant of
two forces can be zero , when they have : -
A ) same magnitude
and opposite direction .
B ) same magnitude
and same direction .
C ) opposite magnitude
and same direction .
D ) opposite
magnitude and opposite direction .
Correct option :
- A ) same magnitude and opposite
direction .
3 ) The maximum and
minimum magnitudes of resultant of given vectors are 17 units and 7 units . If
these two vectors are at right angles to each other , then magnitude of their
resultant is : -
A ) 5 , B
) 13 ,
C ) 44 , D
) None of these ,
Correct Answer :
- B ) 13 ,
Solution : -
Let two vectors a
and b .
According to
question : -
a + b = 17 and
a – b = 7 .
So , a = 12
and b = 5 .
So , R
= √ ( a ^ 2 + b ^ 2 )
R = √ ( 144 + 25 )
= 13 ,
Answer .
OR
4 ) Two forces P and Q have a resultant perpendicular to P . The angle between the force is : -
Solution : -
