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The current in a circuit is defined as I=dqdt. The charge (q) flowing through a circuit, as a function of time (t), is given by q=5t2-20t+3. The minimum charge flows through the circuit at:

  • t=4 sec

  • t=2 sec

  • t= 6 sec

  • t=3 sec

The current in a circuit is defined as I=dqdt. If the charge (q) flowing through a circuit is given by q=(t2-3t+4), current flowing through the circuit is equal to zero at:

  • t=3 sec

  • t=2 sec

  • t=1.5 sec

  • t=15 sec

Work done by a force (F) in displacing a body by dx is given by W=F(x).dx. If the force is given as a function of displacement (x) by F(x)=(x2-2x+1)N, then work done by the force from x=0 to x=3 m is:

  • 3 J

  • 6 J

  • 9 J

  • 21 J

The impulse due to a force on a body is given by I=Fdt. If the force applied on a body is given as a function of time (t) as F=(3t2+2t+5)N, then impulse on the body between t=3 sec to t = 5 sec is:

  • 216 kg-m/sec

  • 124 kg-m/sec

  • 175 kg-m/sec

  • 41 kg-m/sec

Which of the following option is not true, if A = 3ˆi + 4ˆj and B = 6ˆi + 8ˆj, where A and B are the magnitudes of A and B?

  • A × B = 0

  • AB = 12

  • A·B = 48

  • A = 5

The angle made by the vector A = 3ˆi + 3ˆj + 2ˆk with y-axis is:

  •   sin-1(314)

  •   sin-1(74)

  •   cos-1(43)

  •   cos-1(35)

In the space, if the sum of vectors of unequal magnitude is zero, then the minimum number of vectors are

  • 2

  • 3

  • 4

  • 5

If A + B is perpendicular to A - B  , then which of the following statement is correct?

  •   |A| = |B|

  •   A  B

  •   A·B = zero

  •   (A + B)·(A - B)  0

The angle between the two vectors (-2ˆi + 3ˆj + ˆk) and (ˆi + 2ˆj - 4ˆk) is:

  • 90°

  • 180°

  • 45°

If a + b + c = 0; then which of the following statements is incorrect?

  • a, b and c must each be a null vector.

  • The magnitude of a+b equals the magnitude of c.

  • The magnitude of ä can never be greater than the sum of the magnitudes of b and c

  • ä must lie in the plane of b and c.

When a force of magnitude F acts on a body of mass m the acceleration produced in the body is
a. If three coplanar forces of equal magnitude F act on the same body as shown in the figure, then acceleration produced is

                                

1.  0

2.  (3 +1)a

3.  (3 -1)a

4.  3a>

  • 1
  • 2
  • 3
  • 4

Three forces each of magnitude 1 N act along with the sides AB, BC, and CD of a regular hexagon. The magnitude of their resultant is:

                                

  • 4N 

  • Zero

  • 2 N

  • 1 N

If a unit vector ˆj is rotated through an angle of 45° anticlockwise, then the new vector will be:

  •   2ˆi + 2ˆj

  •   ˆi + ˆj

  •   12ˆi + 12ˆj

  •   -12ˆi + 12ˆj

If a = 2ˆi + ˆj and b = 3ˆi + 2ˆj, then |a × b|=? 

  •   1

  •   65

  •   8

  •   4 

A and B are two vectors given by A = 2ˆi + 3ˆj and B = ˆi + ˆj. The component of →   Aparallel to B is:

  •   12(2ˆi - ˆj)

  •   52(ˆi - ˆj)

  •   52(ˆi + ˆj)

  •   (3ˆi - 2ˆj)2

If a vector is inclined at angles, α, β, and γ with x, y, and z-axis respectively, then the value of sin2 α + sin2 β+ sin2 γ is equal to

  • 0

  • 1

  • 2

  • 12

If ˆp is the unit vector in the direction B, then:

  •   ˆp = |B|B

  •   ˆp = |B| × B

  •   ˆp = B|B|

  •   ˆp = BB

Which of the following sets of forces cannot give zero resultant?

  • 3 N, 4 N, 5 N

  • 9 N, 8 N, 7 N

  • 16 N, 2 N, 17 N

  • 30 N, 5 N, 24 N

The minimum number of non-coplanar vectors whose vector sum can be zero is:

  • 2

  • 3

  • 4

  • 5

The resultant vector of P and Q makes angle θ1 with P and θ2 with Q.Then-

  •   θ1 > θ2

  •   θ1 < θ2 if P > Q

  •   θ1 < θ2 if P < Q

  •   θ1 > θ2 if P = Q

A vector A, which has magnitude 8.0 is added to a vector B which lies on the x-axis. The sum of these two vectors lies on the y-axis and has a magnitude twice the magnitude of B. The magnitude of the vector B

  •   85

  •   8

  •   2 × 8

  •   85

If A = 2ˆi + 3ˆj + 6ˆk and B = 3ˆi + 2ˆj - ˆk, then the unit vector in the direction of A + B is

  •   (ˆi - ˆj - ˆk)3

  •   (ˆi + ˆj - ˆk)3

  •   (ˆi + ˆj + ˆk)3

  •   (ˆi - ˆj + ˆk)3

The forces F1 and F2 are acting perpendicular to each other at a point and have resultant R. If force F2 is replaced by R2 - F21F2 acting in the direction opposite to that of F2, the magnitude of resultant

  • Becomes half

  • Becomes double

  • Becomes one third

  • Remains the same

A force of 20 N acts on a particle along a direction, making an angle of 60° with the vertical. The component of the force along the vertical direction will be

  • 2 N

  • 5 N

  • 10 N

  • 20 N

If A and B are two vectors inclined to each other at an angle θ, then the component of A perpendicular to B and lying in the plane containing A and B will be:

  •   A.BB2B

  •   A - A.BB2B

  •   A - B

  •   A + B

If |A|  |B| and |A × B| = |A · B|, then 

  •   A  B

  •   A  B

  •   A is antiparallel to B

  •   A is inclined to B at an angle of 45°

If R is the resultant of two vectors A and B and R' is the difference in them, and |R| = |R'|, then:

  • A  B

  • A  B

  • A is antiparallel to B

  • A makes an angle of 120° with B

Two forces of the same magnitude are acting on a body in the East and North directions, respectively. If the body remains in equilibrium, then the third force should be applied in the direction of:

  • North-East

  • North-West

  • South-West

  • South-East

Given are two vectors,  A= (2ˆi - 5ˆj + 2ˆk) and B = (4ˆi - 10ˆj + cˆk). What should be the value of c so that vector A and B would become parallel to each other?

  •   1

  •   2

  •   3

  •   4

In the following questions, a statement of assertion (A) is followed by a statement of the reason (R).

 

A: A vector must have, magnitude and direction.

R: A physical quantity cannot be called a vector if its magnitude is zero.

  • If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1).

  • If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2).

  • If Assertion is a true statement but Reason is false, then mark (3).

  • If both Assertion and Reason are false statements, then mark (4).

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