Kinematics PYQs Set 8 (PDF)

Set 8 of 14 · Questions 211-240 of 405

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Mere Teacher · Previous Year Questions JEE Main Physics · Kinematics · Set 8 (Q211-240)
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211. $Which of the following options is correct for the object having a straight-line motion represented by the following graph?$ (1) $The object moves with constantly increasing velocity from O to A and then it moves with constant velocity.$ (2) $Velocity of the object increases uniformly.$ (3) $Average velocity is zero.$ (4) $The graph shown is impossible.$ 212. $Water drops are falling from a nozzle of a shower onto the floor, from a height of 9.8m. The drops fall at a regular interval of time. When the first drop strikes the floor, at that instant, the third drop begins to fall. Locate the position of second drop from the floor when the first drop strikes the floor.$ (1) $4.18m$ (2) $2.94m$ (3) $2.45m$ (4) $7.35m$ 213. $If a ball is thrown vertically upwards with speed u, the distance covered during the last t seconds of its ascent is$ (1) $u t$ (2) $\frac{1}{2} g t^{2}$ (3) $u t - \frac{1}{2} g t^{2}$ (4) $(u + g t) t$ 214. $Two stones are thrown up simultaneously from the edge of a cliff 240 m high with initial speed of 10 m/s and 40 m/s respectively. Which of the following graph best represents the time variation of relative position of the second stone with respect to the first ? (Assume stones do not rebound after hitting the ground and neglect air resistance, take g = 10 m/ s^{2}) (The figures are schematic and not drawn to scale.)$ (1) (2) (3) (4) 215. $For the following velocity-time graph, the average speed for the motion during first 80 s is$ (1) $0$ (2) $5 m / s$ (3) $10 m / s$ (4) $0.25 m / s$ 216. $The speed of a swimmer in still water is 20 m / s . The speed of river water is 10 m / s and is flowing due east. If he is standing on the south bank and wishes to cross the river along the shortest path the angle at which he should make his strokes w.r.t. north is given by [NEET 2019]$ (1) $0^{\circ}$ (2) $60^{\circ} west$ (3) $45^{\circ} west$ (4) $30^{\circ} west$ 217. $A body is projected with a speed u at an angle θ with the horizontal. The radius of curvature of the trajectory, when it makes an angle (\frac{θ}{2})^{\circ} with the horizontal is (g-acceleration due to gravity)$ (1) $\frac{u ^{2} cos ^{2} θ sec ^{3} ( \frac{θ}{2} )}{3 g}$ (2) $\frac{u ^{2} cos ^{2} θ sec ^{3} ( \frac{θ}{2} )}{2 g}$ (3) $\frac{2 u ^{2} cos ^{3} θ sec ^{2} ( \frac{θ}{2} )}{g}$ (4) $\frac{u ^{2} cos ^{2} θ sec ^{3} ( \frac{θ}{2} )}{g}$ 218. $A balloon was moving upwards with a uniform velocity of 10m/s. An object of finite mass is dropped from the balloon when it was at a height of 75m from the ground level. The height of the balloon from the ground when object strikes the ground was around (takes the value of g as 10m/ s^{2})$ (1) $300m$ (2) $200m$ (3) $125m$ (4) $250m$ 219. $Two cars A and B are moving with a velocity of 30 km / h in the same direction. They are separated by 10 km . The speed of another car C moving in the opposite direction, if it meets these two cars at an interval of eight minutes is$ (1) $45 km / h$ (2) $40 km / h$ (3) $15 km / h$ (4) $30 km / h$ 220. $The displacement x versus time graph is shown below. (A) The average velocity during 0 to 3 s is 10 m / s (B) The average velocity during 3 to 5 s is 0 m/s(C) The instantaneous velocity at t = 2 s is 5 m / s (D) The average velocity during 5 to 7 s and instantaneous velocity at t = 6.5 s are equal (E) The average velocity from t - 0 to t - 9 s is zero Choose the correct answer from the options given below:$ (1) $(B), (C), (D) only$ (2) $(B), (D), (E) only$ (3) $(A), (D), (E) only$ (4) $(B), (C), (E) only$ 221. $A body is falling freely from a point A at a certain height from the ground and passes through points B, C and D (vertically as shown below) so that BC = CD . The time taken by the particle to move from B to C is 2 s and from C to D is 1 s . Time taken to move from A to B in seconds is$ (1) $0.6$ (2) $0.5$ (3) $0.2$ (4) $0.4$ 222. $The motion of an airplane is represented by velocity-time graph as shown below. The distance covered by airplane in the first 30.5 second is km$ (1) $12$ (2) $3$ (3) $6$ (4) $9$ 223. $Train A is moving along two parallel rail tracks towards north with speed 72 km / h and train B is moving towards south with speed 108 km / h . Velocity of train B with respect to A and velocity of ground with respect to B are (in ms^{- 1}) :$ (1) $- 30 and 50$ (2) $-50 and -30$ (3) $-50 and 30$ (4) $50 and -30$ 224. $An object moving with a speed of 6.25 m/s, is decelerated at a rate given by: \frac{d v}{d t} = - 2.5 v where v is the instantaneous speed. The time taken by the object, to come to rest, would be:$ (1) $1 s$ (2) $2 s$ (3) $4 s$ (4) $8 s$ 225. $A rocket moves straight upward with zero initial velocity and with an acceleration 20 m / s^{2} . It runs out of fuel and stops accelerating at the end of 5^{th} sec . It reaches a maximum height and falls back to the earth. The speed when it hits the ground is .(Take g = 10 m / s^{2})$ (1) $1002 m / s$ (2) $1503 m / s$ (3) $506 m / s$ (4) $. 75 m / s$ 226. $Water droplets are coming from an open tap at particular rate. The spacing between a droplet observed at 4^{t h} second after its fall to the next droplet is 34.3m. At what rate the droplets are coming from the tap ? (Take g=9.8m/ s^{2})$ (1) $3 drops/2 seconds$ (2) $2 drops / second$ (3) $1 drop / second$ (4) $1 drop /7seconds$ 227. $A person travels x distance with velocity v_{1} and then x distance with velocity v_{2} in the same direction. The average velocity of the person is v, then the relation between v, v_{1} and v_{2} will be$ (1) $v = \frac{v _{1} + v _{2}}{2}$ (2) $\frac{1}{v} = \frac{1}{v _{1}} + \frac{1}{v _{2}}$ (3) $v = v_{1} + v_{2}$ (4) $\frac{2}{v} = \frac{1}{v _{1}} + \frac{1}{v _{2}}$ 228. $When an object is shot from the bottom of a long smooth inclined plane kept at an angle 60^{\circ} with horizontal, it can travel a distance x_{1} along the plane. But when the inclination is decreased to 30^{\circ} and the same object is shot with the same velocity, it can travel x_{2} distance. Then, x_{1} : x_{2} will be [NEET 2019]$ (1) $2 : 1$ (2) $1 : 3$ (3) $1 : 23$ (4) $1 : 2$ 229. $A particle shows distance-time curve as shown in the figure. The maximum instantaneous velocity of the particle is around the point$ (1) $P$ (2) $S$ (3) $R$ (4) $Q$ 230. $A ship A is moving westwards with a speed of 10 km h^{- 1} and a ship B 100 km south of A, is moving northwards with a speed of 10 km h^{- 1} . The time after which the distance between them becomes shortest is$ (1) $0 h$ (2) $5 h$ (3) $52 h$ (4) $102 h$ 231. $A body is moving with an initial velocity of 102 ms^{- 1} in the north-east direction. If it is subjected to an acceleration of 2 ms^{- 2} directed towards the south, then velocity of the body after 5 s is$ (1) $10 ms^{- 1}, towards east$ (2) $10 ms^{- 1}, towards north$ (3) $10 ms^{- 1}, towards south$ (4) $10 ms^{- 1}, towards north-east$ 232. $A ball is thrown up vertically with a certain velocity so that, it reaches a maximum height h. Find the ratio of the times in which it is at height \frac{h}{3} while going up and coming down respectively.$ (1) $\frac{2 - 1}{2 + 1}$ (2) $\frac{3 - 2}{3 + 2}$ (3) $\frac{3 - 1}{3 + 1}$ (4) $\frac{1}{3}$ 233. $The velocity-time graph of an object moving along a straight line is shown in figure. What is the distance covered by the object between t = 0 to t = 4 s ?$ (1) $30 m$ (2) $11 m$ (3) $10 m$ (4) $13 m$ 234. $A body is moving with velocity 30 m / s towards east. After 10 seconds its velocity becomes 40 m / s towards north. The average acceleration of the body is$ (1) $1 m / s^{2}$ (2) $7 m / s^{2}$ (3) $7 m/s^{2}$ (4) $5 m / s^{2}$ 235. $A plane is inclined at an angle α = 30^{\circ} with respect to the horizontal. A particle is projected with a speed u = 2 ms^{- 1}, from the base of the plane, as shown in figure. The distance from the base, at which the particle hits the plane is close to:(Take g = 10 ms^{- 2}$ (1) $20 cm$ (2) $18 cm$ (3) $26 cm$ (4) $14 cm$ 236. $In a spring gun having spring constant 100N/m a small ball 'B' of mass 100g is put in its barrel (as shown in figure) by compressing the spring through 0.05m. There should be a box placed at a distance 'd' on the ground so that the ball falls in it. If the ball leaves the gun horizontally at a height 2m of above the ground. The value of d is ___ m.(g=10m/ s^{2})$ 237. $Two cars P and Q are moving on a road in the same direction. Accleration of car P increases linearly with time whereas car Q moves with a constant accleration. Both cars cross each other at time t = 0, for the first time. The maximum possible number of crossing(s) (including the crossing at t = 0) is .$ 238. $From the top of a tower, a ball is thrown vertically upward which reaches the ground in 6 s. A second ball thrown vertically downward from the same position with the same speed reaches the ground in 1.5 s. A third ball released, from the rest from the same location, will reach the ground in________s.$ 239. $A body falling under gravity covers two points A and B separated by 80 m in 2 s . The distance of upper point A from the starting point is_______m (use (g = 10 ms^{- 2})$ 240. $The speed of a swimmer is 4 km h^{- l} in still water. If the swimmer makes his strokes normal to the flow of river of width 1 km, he reaches a point 750 m down the stream on the opposite bank. The speed of the river water is_______km h^{- 1} .$