Tiêu đề 3.MOTION IN A STRAIGHT LINE - Questions.pdf ✅

3.MOTION IN A STRAIGHT LINE (1.)A river is flowing from W to E with a speed of 5 m/min. A man can swim in still water with a velocity 10 m/min. In which direction should the man swim so as to take the shortest possible path to go to the south (a.) 30° with downstream (b.) 60° with downstream (c.) 120° with downstream (d.) South (2.)A train started from rest from a station and accelerated at 2 ms−2 for 10 s. Then, it ran at constant speed for 30 s and thereafter it decelerated at 4 ms−2 until it stopped at the next station. The distance between two stations is (a.) 650 m (b.) 700 m (c.) 750 m (d.) 800 m (3.)From a balloon rising vertically upwards as 5 ms−1 a stone is thrown up at 10 ms−1 relative to the balloon. Its velocity with respect to ground after 2 s is (assume g = 10 ms−2) (a.) Zero (b.) 5ms−1 (c.) 10 ms−1 (d.) 20 ms−1 (4.)An object is dropped from rest. Its v-t graph is (a.) (b.) (c.) (d.) (5.)A stone is allowed to fall from the top of a tower 100m high and at the same time another stone is projected vertically upwards from the ground with a velocity of 254ms −1 . The two stones will meet after (a.) 4 s (b.) 0.4 s (c.) 0.04 s (d.) 40 s (6.)A body starting from rest moves with constant acceleration. The ratio of distance covered by the body during the 5th sec to that covered in 5 sec is (a.) 9/15 (b.) 3/5 (c.) 25/9 (d.) 1/25 (7.)If a car at rest accelerates uniformly to a speed of 144 km/h in 20 s. Then it covers a distance of (a.) 20 m (b.) 400 m (c.) 1440m (d.) 2880 m (8.)A body is projected up with a speed ‘u′ and the time taken by it is T to reach the maximum height H. Pick out the correct statement (a.) It reaches H/2 in T/2 sec (b.) It acquires velocity u/2 in T/2sec (c.) Its velocity is u/2 at H/2 (d.) Same velocity at 2T (9.)Two balls are dropped to the ground from different heights. One ball is dropped 2s after the other but they both strike the ground at the same time. If the first ball takes 5s to reach the ground, then the difference in initial heights is (g = 10 ms −2 ) (a.) 20m (b.) 80m (c.) 170m (d.) 40m (10.)A car accelerates from rest at a constant rate of 2ms−2 for sometime. Then, it retards at a constant rate of 4ms −2 and comes to rest. If the total time for which it remains in motion is 3s, what is the total distance travelled? (a.) 2m (b.) 3m (c.) 4m (d.) 6m (11.)When a ball is thrown up vertically with velocity V0 , it reaches a maximum height of ′h′. If
one wishes to triple the maximum height then the ball should be thrown with velocity (a.) √3V0 (b.) 3V0 (c.) 9V0 (d.) 3/2V0 (12.)A cyclist starts from the centre O of a circular park of radius one kilometre, reaches the edge P of the park, then cycles along the circumference and returns to the centre along QO as shown in figure. If the round trip takes ten minutes, the net displacement and average speed of the cyclist (in metre and kilometre per hour) is (a.) 0, 1 (b.) π+4 2 , 0 (c.) 21.4, π+4 2 (d.) 0, 21.4 (13.)A train of 150 m length is going towards north direction at a speed of 10m/sec. A parrot flies at the speed of 5 m/sec towards south direction parallel to the railway track. The time taken by the parrot to cross the train is (a.) 12 sec (b.) 8 sec (c.) 15 sec (d.) 10 sec (14.)Two cars A and B are moving with same speed of 45 kmh−1 along same direction. If a third car C coming from the opposite direction with a speed of 36 kmh−1 meets two cars in an interval of 5 min, the distance of separation of two cars A and B should be (in km) (a.) 6.75 (b.) 7.25 (c.) 5.55 (d.) 8.35 (15.)A person travels along a straight road for the first half time with a velocity v1 and the next half time with a velocity v2 The mean velocity V of the man is (a.) 2 V = 1 v1 + 1 v2 (b.) V = v1+v2 2 (c.) V = √v1v2 (d.) V = √ v1 v2 (16.)A particle starts from rest and traverses a distance 2x with uniform acceleration, then moves uniformly over a further distance 4x and finally comes to rest after moving a further distance 6x under uniform retardation. Assuming entire motion to be rectilinear motion, the ratio of average speed over the journey to the maximum speed on its way is (a.) 4/5 (b.) 3/5 (c.) 2/5 (d.) 1/5 (17.)A body is projected with a velocity v and after some time it returns to the point from which it was projected. The average velocity and average speed of the body for the total time of flight are (a.) v⃗/2 and v/2 (b.) 0 and v/2 (c.) 0 and 0 (d.) v⃗/2 and 0 (18.)An athlete completes one round of a circular track of radius R in 40 sec. What will be his displacement at the end of 2 min. 20 sec (a.) Zero (b.) 2R (c.) 2πR (d.) 7πR (19.)Acceleration-time graph of a body is shown. The corresponding velocity-time graph of the same body is (a.) (b.) (c.) (d.) (20.)A stone thrown vertically upwards attains a maximum height of 45m. In what time the velocity a t v t v t v t v t
of stone become equal to one-half the velocity of throw? (Given g = 10ms −2 ) (a.) 2 s (b.) 1.5 s (c.) 1 s (d.) 0.5 s (21.)A particle starts from the origin and moves along the X-axis such that the velocity at any instant is given by 4t 3 − 2t, where t is in second and velocity is in ms −1 . What is the acceleration of the particle when it is 2 m from the origin? (a.) 10ms −2 (b.) 12ms −2 (c.) 22ms −2 (d.) 28ms −2 (22.)A body is thrown vertically upwards with velocity u. The distance travelled by it in the fifth and the sixth seconds are equal. The velocity u is given by (g = 9.8 ms−2) (a.) 24.5 ms−1 (b.) 49.0 ms−1 (c.) 73.5 ms−1 (d.) 98.0 ms−1 (23.)A body falling from a high Minaret travels 40 m in the last 2 seconds of its fall to ground. Height of Minaret in meters is (take g = 10 m/s −2 ) (a.) 60 (b.) 45 (c.) 80 (d.) 50 (24.)A 2 m wide truck is moving with a uniform speed v0 = 8ms −1 along a straight horizontal road. A pedestrian starts to cross the road with a uniform speed v when the truck is 4m away from him. The minimum value of v, so that he can cross the raod safely is (a.) 2.62ms −1 (b.) 4.6ms −1 (c.) 3.57ms −1 (d.) 1.414ms −1 (25.)From a high tower at time t = 0, one stone is dropped from rest and simultaneously another stone is projected vertically up with an initial velocity. The graph of the distance S between the two stones, before either his the ground, plotted against time t will be as (a.) (b.) (c.) (d.) (26.)A balloon starts rising from the ground with an acceleration of 1.25 m/s 2 after 8s, a stone is released from the balloon. The stone will (g − 10 m/s 2 ) (a.) Reach the ground in 4 second (b.) Begin to move down after being released (c.) Have a displacement of 50 m (d.) Cover a distance of 40 m in reaching the ground (27.)A ball is thrown vertically upwards. Which of the following graph/graphs represent velocity-time graph of the ball during its flight (air resistance is neglected) (a.) A (b.) B (c.) C (d.) D (28.)A body starting from rest moves with uniform acceleration. The distance covered by the body in time t is proportional to (a.) √t (b.) t 3/2 (c.) t 2 (d.) t 3 t v (a) t v (b) t v (c) t v (d)
(29.)A car starts from rest and accelerates uniformly to a speed of 180 kmh −1 in 10 seconds. The distance covered by the car in this time interval is (a.) 500 m (b.) 250 m (c.) 100 m (d.) 200 m (30.)v − t graph for a particle is as shown. The distance travelled in the first 4 s is (a.) 12m (b.) 16m (c.) 20m (d.) 24m (31.)A body is moving according to the equation x = at + bt 2 − ct 3 where x = displacement and a, b and c are constants. The acceleration of the body is (a.) a + 2bt (b.) 2b + 6ct (c.) 2b − 6ct (d.) 3b − 6ct 2 (32.)A car starts from station and moves along the horizontal road by a machine delivering constant power. The distance covered by the car in time t is proportional to (a.) t 2 (b.) t 3/2 (c.) t 2/3 (d.) t 3 (33.)A particle when thrown, moves such that it passes from same height at 2 and 10s, the height is (a.) g (b.) 2g (c.) 5g (d.) 10g (34.)Which graph represents a state of rest for an object (a.) (b.) (c.) (d.) (35.)Rain drops fall vertically at a speed of 20ms −1 . At what angle do they fall on the wind screen of a car moving with a velocity of 15ms −1 , if the wind screen velocity inclined at an angle of 23° to the vertical? (cot−1 [ 4 3 ] ≈ 36°) (a.) 60° (b.) 30° (c.) 45° (d.) 90° (36.)Time taken by an object falling from rest to cover the height of h1 and h2 is respectively t1 and t2 then the ratio of t1 to t2 is (a.) h1: h2 (b.) √h1: √h2 (c.) h1: 2h2 (d.) 2h1: h2 (37.)A body starts to fall freely under gravity. The distance covered by it in first, second and third second are in ratio (a.) 1: 3: 5 (b.) 1: 2: 3 (c.) 1: 4: 9 (d.) 1: 5: 6 (38.)Two balls A and B of same masses are thrown from the top of the building. A, thrown upward with velocity V and B, thrown downward with velocity V, then (a.) Velocity of A is more than B at the ground (b.) Velocity of B is more than A at the ground (c.) Both A & B strike the ground with same velocity (d.) None of these (39.)A body is thrown vertically up from the ground. It reaches a maximum height of 100m in 5sec. After what time it will reach the ground from the maximum height position (a.) 1.2 sec (b.) 5 sec (c.) 10 sec (d.) 25 sec (40.)The distance travelled by a particle is proportional to the square of time, then the particle travels with (a.) Uniform acceleration (b.) Uniform velocity (c.) Increasing acceleration (d.) Decreasing velocity