The displacement of a particle is given by y=a+bt+ct2-dt4. The initial velocity and initial acceleration, respectively, are: (Given:v=dxdt and a=d2xdt2)
b, -4d
-d, 2c
b, 2c
2c, -4d
The momentum is given by p=4t+1, the force at t=2s is-[Given: F=dPdt]
() 4 N
() 8 N
() 10 N
() 15 N
If the momentum of a particle is given by P=(180-8t) kg m/s, then its force will be-[Given: F=dPdt]
Zero
8 N
-8 N
4 N
If f(x)=x2-2x+4, then f(x) has:
a minimum at x=1.
a maximum at x=1.
no extreme point.
no minimum.
A particle is moving along x-axis. The velocity v of particle varies with its position x as v=1x. Find velocity of particle as a function of time t given that at t=0, x=1 .
v=√2t+1
v=1√2t+1
v=1t
None of these
A vector →A is directed along 30° west of north direction and another vector →B along 15° south of east. Their resultant cannot be in ____________ direction.
North
East
North-East
South
ABCD is a quadrilateral. Forces →BA, →BC, →CD & →DA act at a point. Their resultant is
() 2 →AB
() 2 →DA
() zero vector
() 2 →BA
The maximum and minimum magnitude of the resultant of two vectors are 17 units and 7 units respectively. Then the magnitude of resultant of the vectors when they act perpendicular to each other is:
14
16
18
13
A vector →A makes an angle of 20° and →B makes an angle of 110° with the X-axis. The magnitudes of these vectors are 3 m and 4 m respectively. Find the magnitude of the resultant.
() 1
() 5√2
() 5
() 7
A particle is moving westward with a velocity →vi=5 m/s. Its velocity changed to →vf=5m/s northward. The change in velocity vector (∆→V=→vf-→vi) is:
5√2 m/s towards north east
5 m/s towards north west
zero
5√2 m/s towards north west
Consider east as positive x-axis, north as positive y-axis and vertically upward direction as z-axis. A helicopter first rises up to an altitude of 100 m than flies straight in north 500 m and then suddenly takes a turn towards east and travels 1000 m east. What is position vector of helicopter. (Take starting point as origin)
1000 ˆi-500 ˆj+100 ˆk
1000 ˆi+500 ˆj-100 ˆk
1000 ˆi+500 ˆj+100 ˆk
-1000 ˆi+500 ˆj+100 ˆk
A force →F=6ˆi-8ˆj+10ˆk Newton produces acceleration 1 m/s2 in a body. The mass of the body is (in kg)
6ˆi-8ˆj+10ˆk
100
10√2
10
Given the vectors
→A=2ˆi+3ˆj-ˆk →B=3ˆi-2ˆj-2ˆk& →C=pˆi+pˆj+2pˆk
Find the angle between (→A-→B) & →C
(A) θ=cos-1(2√3)
(B) θ=cos-1(√32)
(C) θ=cos-1(√23)
(D) none of these
The vector having a magnitude of 10 and perpendicular to the vector 3ˆi-4ˆj is-
4ˆi-3ˆj
5√2 ˆi-5√2 ˆj
8ˆi+6ˆj
8ˆi-6ˆj
A force →F=3ˆi+cˆj+2ˆk acting on a particle causes a displacement →d=-4ˆi+2ˆj+3ˆk. If the work done is 6J then the value of 'c' is- [Given: W=→F.→d]
() 12
() 0
() 6
A particle moving along a straight line according to the law x=At+Bt2+Ct3, where x is its position measured from a fixed point on the line and t is the time elapsed till it reaches position x after starting from the fixed point. Here A, B and C are positive constants.
Its velocity at t=0 is A
Its acceleration at t=0 is B
Its velocity at t=0 is B
Its acceleration at t=0 is C
If the velocity of a particle moving on x-axis is given by v=3t2-12t+6. At which time is the acceleration of particle zero?
2 sec
2+√2 sec
2-√2 sec
Momentum of a body moving in a straight line is p=(t2+2t+1) kg m/s. Find the force acting on a body at t=2 sec
6 N
2 N
A particle moves along straight line such that at time t its position from a fixed point O on the line is x=3t2-2. The velocity of the particle when t=2 is:
() 8 ms-1
() 4 ms-1
() 12 ms-1
Coordinates of a moving particle are given by x=ct2 and y=bt2. The speed of the particle is given by
2t (c+b)
2t √c2-b2
t √c2+b2
2t √c2+b2
The x and y components of vector →A are 4m and 6m respectively. The x, y components of vector →A+→B are 10m and 9m respectively. The length of →B is ______ and angle that →B makes with the x axis is given by _______.
(A) 0.45m, tan-11/2
(B)&nsp; √4.5m, tan-1(1/2)
(C) √45m, tan-1(1/2)
(D) 4√5m, tan-1Unknown node type: mfence
A particle travels with speed 50 m/s from the point (3, 7) in a direction 7ˆi-24ˆj. Find its position vector after 3 seconds.
() 151ˆi+45ˆj
() 45ˆi-137ˆj
() 4.5ˆi-151ˆj
If →a is a vector and x is a non-zero scalar, then which of the following is correct?
If θ is the angle between two vectors →a and →b, and |→a×→b|=→a.→b, then θ is equal to:
0°
180°
135°
45°
The vector →b, which is collinear with the vector →a=(2, 1, -1) and satisfies the condition →a.→b=3 is-
(1, 1/2, -1/2)
(2/3, 1/3, -1/3)
(1/2, 1/4, -1/4)
(1, 1, 0)
If a, b and c are three non-zero vectors such that →a+→b+→c=0, then the value of →a.→b+→b.→c+→c.→a will be:
Less than zero
equal to zero
greater than zero
3
Two vectors →a and →b inclined at an angle θ w.r.t. each other have a resultant →c which makes an angle β with →a. If the directions of →a and →b are interchanged, then the resultant will have the same
(A) mgnitude
(B)&nsp; direction
(C) magnitude as well as diretion
(D) neither magnitue nor direction
Two vectors →A and →B lie in a plane. Another vector →C lies outside this plane. The resultant →A+→B+→C of these three vectors
can be zero
cannot be zero
lies in the plane of →A &→B
lies in the plane of →A & →A+→B
The vector sum of the forces of 10 N and 6 N can be
18 N
20 N
A set of vectors taken in a given order gives a closed polygon. Then the resultant of these vectors is a
scalar quantity
pseudovector
unit vector
null vector
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