Q381.The equation x y ccosh, c = where c is a constant, represents:
Correct answer: Common catenary
Q382.A horizontal shelf is moved up and down with S.H.M. of period 1 2 sec. The greatest amplitude admissible in order that a weight placed on the shelf may not be jerked off, is:
Correct answer: 2 g 16π
Q383.Three equal coplanar forces of weight 10kg acting at a point. If their lines of action are making same angle, then resultant force is
Correct answer: 0
Q384.In a ∆ ∆ ∆ ABC, let ∠ ∠ ∠C 2 π =. If r and R are the inradius and the circumradius respectively of the triangle, then 2(r+R) is equal to
Correct answer: a+b
Q385.The resultant of two forces P and Q is R. If Q is doubled, R is also doubled and if the direction of Q is reversed, R is again doubled. If the ration P:Q: R:: 2: 3: x then x is equal
Correct answer: 2
Q386.The distance s in cm traversed by a particle in t second is given by the equation s=4t3 –5t+3. Then the velocity of the particle after 3 sec is
Correct answer: 103cm/sec
Q387.A stone is dropped into a well and the sound of the splash is hear 11.5 second later by the person who dropped the stone. If the velocity of the sound is 327m/s, then the approximate depth of the well in metres is
Correct answer: 490.5m
Q388.A stone is thrown horizontally, with velocity 2gh from the top of a tower of height h. The distance where it will strike the level ground through the foot of the tower is
Correct answer: 2h
Q389.A ball A moving with velocity u, impinges directly on an equal ball B moving with velocity v in the opposite direction. If the coefficient of elasticity is e and after the impact ball A comes to rest, then u v =
Correct answer: 1 e + −
Q390.A sphere impinges directly on an equal sphere at rest. If the coefficient of restitution is e, then the ratio of their velocities after the impact is
Correct answer: 1– e: 1+ e
Q391.The resultant of two force is P newton and 3 newton is 7 newton. If the directive of a force of 3 newton is changed then the resultant force becomes 19 newtons. The value of P is.
Correct answer: 5N
Q392.If POB is a diameter of a circle and points P, a, B and Q lies on the circle. If angle ∠ ∠ ∠ABP = 60o then ∠ ∠ ∠BOA is–
Correct answer: 300
Q393.A motor car weighing 10 quintals travels at 12m/sec. It is moving with the speed of the brake is applied for a sudden stop at a distance of 18 m. the resistance to the work done by the force is –
Correct answer: None of these
Q394.The mass of the body is 2 kg. It is thrown vertically upward with a velocity 1000 cm/sec. What will be its kinetic energy after 1 second?
Correct answer: 361000 erg
Q395.A train starts at a distance from a station 'A' with uniform acceleration 'f1' and them stops at station B after traveling a certain distance with uniform retardation 'f2'. the distance between station 'a' and station 'B' is 4 km and it takes 4 minutes to cover the distance. If F1 and F2 are in unit km/minutes2 then 1 2 1 1 + = f f
Correct answer: 2
Q396.Another sphere of the same size collides with a stationary sphere. If the velocity of separation (or the coefficient of elasticity) of both after the collision is 'e', the what will be the ratio of the velocity of two spheres after the collision?
Correct answer: 1–e: 1 + e
Q397.If a particle is projected vertically up words and reaches a height 'h' after time 't'. Again after taking 't' time he comes to the ground then h =
Correct answer: 1 gtt' 2
Q398.The equation of motion of the particle moving along a straight line is x = 1 2 vt; where x is the distance. and v is the velocity of the particle at any instant 't' Then the acceleration of the particle is
Correct answer: proportional to distance
Q399.If the greatest and the least resultants of two forces are P and Q respectively, then the resultant of these forces, when acting at right angles, will be:
Correct answer: 2 2 (P Q) 2 +
Q400.ABC is a uniform triangular lamina with centre of gravity G. If the portion GBC is removed, the centre of gravity of the remaining portion is at G'. then GG' is equal to:
Correct answer: 1 AG 6