Q.1
For any two vectors A and B if A.B=|A×B|, the magnitude of C=A + B is equal to
  • a) √( A2 + B2)
    ch-3_qn-219choice_img_no3.png
  • b) A + B
    ch-3_qn-219choice_img_no4.png
  • c)
  • d)
Q.2
A motor ship covers the distance between the two localities on a river in 6 hours down stream and in 8 hours upstream. The speed of the motor ship is how many times that of river?
  • a) 5 times
  • b) 6 times
  • c) 8 times
  • d) 7 times
Q.3
A man moves on a cycle with velocity of 4km/hr. The rain appears to fall on him with velocity of 3km/hr vertically. the actual velocity of the rain is
  • a)7 km/hr
  • b) 5 km/hr
  • c)(4/3) km/hr
  • d)(3/4) km/hr
Q.4
An aeroplane is moving on a circular path with speed 300 km/hr. What is the change in velocity in half revolution?
  • a) zero
  • b) 600 km/hr
  • c)300 km/hr
  • d)300×√2 km/hr
Q.5
A metal sphere is hung by a string fixed to a wall. The sphere is pushed away from the wall by stick. The force acting on the sphere are shown in the second diagram. Which of the following statement is wrong
ch-3_que_no-223_img_no1.png
  • a) P=Wtanθ
  • b) T=P + W=0
  • c)T2=P2 + W2
  • d)T=P + W
Q.6
0.4i 0.8j + c k represents a unit vector when c is
  • a) -0.2
  • b) √(0.2)
  • c) √(0.8)
  • d) 0
Q.7
Two particles starts to move with velocity u and v, along x-axis and y-axis, respectively, from the origin. The acceleration of the first particle with respect to the second, is
  • b) zero
  • c)u+v
  • d)none of these
  • a)√(u² + v²)
Q.8
In the above problem, the velocity of first particle with respect to the second is
  • b) u+v at tan⁻¹(v/u) with x-axis
  • a) √(u² + v²) at tan⁻¹(v/u) with x-axis
  • c)√(u² - v²) at tan⁻¹(v/u) with y-axis
  • d)√(u² + v²) at tan⁻¹(v/u) with y-axis
Q.9
Projection of vector A over B is
  • a)
    ch-3_qn-227choice_img_no1.png
  • b)
    ch-3_qn-227choice_img_no2.png
  • c)
    ch-3_qn-227choice_img_no3.png
  • d)
    ch-3_qn-227choice_img_no4.png
Q.10
TWo particles are projected with same speed but making different angles with horizontal such that their ranges are equal. If the angle of projection is π/3 and its maximum height is y1 then the maximum height of the other is
  • a) 3y1
  • b) 2y1
  • c) y1/2
  • d) y1/3
Q.11
A projectile can have the same range R for two angles of projection. If t1 and t2 be the time of flight in two cases then
  • a)t1t2 ∝ R2
  • b) t1t2 ∝ R
  • c)t1t2 ∝ 1/R
  • d)t1t2 ∝ 1/R2
Q.12
A body is projected up a smooth inclined plane with velocity V from point M as shown in figure. The angle of inclination is 45° and the top of the plane is connected to a well of diameter 40m. If bodt magnes to cross the well. What is the value of V? length of the inlicned plane is 20√23 m)
ch-3_que_no-230_img_no1.png
  • a) 40 m/s
  • b) 40√2 m/s
  • c)20 m/s
  • d)20√2 m/s
Q.13
Range of projectile is same as that for θ and 2θ. The value of θ is :
  • a) 15°
  • b) 30°
  • c)45°
  • d)60°
Q.14
The friction of air causes a vertical resistance of 10% in acceleration due to gravity. The maximum height will be decreased by
  • a) 11%
  • b) 10%
  • c) 9%
  • d) 8%
Q.15
In long jump the maximum force experienced by the athlete is at
  • a)on taking off
  • b) at maximum height
  • c)on landing
  • d)same force throughout
Q.16
The maximum height attained by the projectile is increased by 5%, keeping the angle of projection constant , the percentage change in horizontal range is :
  • a) 5%
  • b) 10%
  • c)15%
  • d)20%
Q.17
At what angle with horizontal should a ball be thrown so that its range R is realted to the time flight as R=5T2, take g=10 ms2.
  • a) 30°
  • b) 45°
  • c)60°
  • d)90°
Q.18
A parallelogram is formed with sides a and b. Let d1 and d2 be the diagonals of the parallelogram. Then a2 + b2=?
  • a)
    ch-3_qn-236choice_img_no1.png
  • b)
    ch-3_qn-236choice_img_no2.png
  • c)
    ch-3_qn-236choice_img_no3.png
  • d)
    ch-3_qn-236choice_img_no4.png
Q.19
A rigid ball moving with a momentum p strikes a plain horizontal surface and is reflected with no change in magnitude of momentum. If the angle of incidence is 45° then the angle between the initial and final direction of the ball is
  • a)30°
  • b) 60°
  • c)90°
  • d)120°
Q.20
A swimmer can swim in still water with speed v and the river flowing with velocity v/To cross the river in shortest time, he should swim at an angle θ with the upstream. The ratio of time taken by the swimmer to swim across in shortest time and shortest distance is
  • a) cosθ
  • b) sinθ
  • c)tanθ
  • d)cotθ
Q.21
Two balls are rolling on a flat smooth table. One ball has velocity components √3j and i while the other has components 2i and 2j. If both start moving simultaneously from the same point, the angle between paths is
  • a) 15°
  • b) 30°
  • c)45°
  • d)60°
Q.22
Resultant of two forces F1 and F2 is of magnitude P. If F2 is reversed, then the resultant id of magnitude Q. The value of P2 + Q2 is
  • a)
    ch-3_qn-240choice_img_no1.png
  • b)
    ch-3_qn-240choice_img_no2.png
  • c)
    ch-3_qn-240choice_img_no3.png
  • d)
    ch-3_qn-240choice_img_no4.png
Q.23
Given A + B=R and A +2B is perpendicular to A, then
  • a)2=R
  • b) B=2R
  • c)B=R
  • d)B2=2R2
Q.24
Component of 3i+4j perpendicular to i+j and in the same plane as (3i + 4j) is
  • a) (1/2) (j - i)
  • b) (3/2) (j - i)
  • c)(5/2) (j - i)
  • d)(7/2) (j - i)
Q.25
An aeroplane is flying at a constant speed v on a circular path. Change in velocity, after the aeroplane has described an angle of 60°
  • a) v/3
  • b) v/2
  • c)v
  • d)2v
Q.26
A helicopter is flying at 36√2 km/hr towards North-East. The wind is blowing at 36 km/hr towards south. The displacement of helicopter in 2 hrs is
  • a) 36 km
  • b) 72 km
  • c) 84 km
  • d) 96 km
Q.27
A is point on wheel rolling on a horizontal road. The radius of the wheel is R. Initially the point A is in contact with the ground. The wheel rolls through half the revolution. The displacement of point A is
  • a)πR
    ch-3_qn-245choice_img_no3.png
  • b) 2πR
    ch-3_qn-245choice_img_no4.png
  • c)
  • d)
Q.28
A ball is projected from the ground at a speed of 10 m/s making an angle of 30° with the horizontal. Another ball is simultaneously released from a point on the vertical line along the maximum height of the second ball if they collide at maximum height is
  • a) 1.0 m
  • b) 1.25 m
  • c)2.0 m
  • d)2.5 m
Q.29
A ball is thrown at different angles with same speed u and from the same point. It has same range in both the cases. If y1 and y2 are maximum height attained, then y1 + y2 is
  • b) 2u2 / g
  • c)u2 / 2g
  • d)u2 / 4g
  • a) u² / g
Q.30
Two particles of same mass are projected from same place with same velocity u, such that their ranges are same. IF h1 and h2 are the maximum heights attained by them, then the ralation between h1, h2 and R is
  • a) R=h1h2
  • b) R2=16h1h2
  • c) R2=h₁/h₂
  • d) R2=(h₁/h₂)²
0 h : 0 m : 1 s