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A body moves for a total of nine seconds starting from rest with uniform acceleration and then with uniform retardation, which is twice the value of acceleration and then stops. The duration of uniform acceleration

1) 3 s 2) 4.5 s 3) 5 s 4) 6 s Answer: 4) 6 s Solution: Let a be the acceleration and the retardation is given as -2a t1 + t2 = 9 sec... View Article

The distance travelled by a particle starting from rest and moving with an acceleration 4/3 ms^–2, in the third second is

1) (10/3) m 2) (19/3) m 3) 6 m 4) 4 m Answer: 1) (10/3) m Solution: Distance travelled by the particle in nth second,... View Article

A particle starts its motion from rest under the action of a constant force. If the distance covered in first 10 seconds is S₁and that covered in the first 20 seconds is S₂then

1) S2 = 2S1 2) S2 = 3S1 3) S2 = 4S1 4) S2 = S1 Answer: 3) S2 = 4S1 Solution: S1 = (1/2) a (10)2 S2 = (1/2) a (20)2 S1/S2 =... View Article

A particle is constrained to move on a straight line path it returns to the starting point after 10 sec. The total distance covered by the particle during this time is 30 m. Which of the following statements about the motion of the particle is false

1) Displacement of the particle is zero 2) Average speed of the particle is 3 m/s 3) Displacement of the particle is 30 m 4) Both (a) and (b)... View Article

A 150 m long train is moving with a uniform velocity of 45 km/hr. The time taken by the train to cross a bridge of length 850 m is

1) 56 sec 2) 68 sec 3) 80 sec 4) 92 sec Answer: 3) 80 sec Solution: Total distance to be covered for crossing the brigde = length of... View Article

Which of the following is a one dimensional motion?

1) Landing of a aircraft 2) Earth revolving around the sun 3) Motion of wheels of moving train 4) Train running on a straight track... View Article

A train has a speed of 60 km/hr. for the first one hour and 40 km/hr. for the next half hour. Its average speedin km/hr. is

1) 50 2) 53.33 3) 48 4) 70 Answer: 2) 53.33 Solution: Distance travelled by train in the first 1 hour is 60 km and the distance... View Article

A car travels half the distance with constant velocity of 40 kmph and the remaining half with a constant velocity of 60 kmph. The average velocity of the car in kmph is

1) 40 2) 45 3) 48 4) 50 Answer: 3) 48 Solution: Let the total distance be 2x Time taken in travelling the first distance x will be t1... View Article

One car moving on a straight road covers one third of the distance with 20 km/hr and the rest with 60 km/hr.The average speed is

1) 40 km/hr 2) 80 km/hr 3) 46 (⅔) km/hr 4) 36 km/hr Answer: 4) 36 km/hr Solution: Average speed = Total distance/total time = x/(t1 +... View Article

An aeroplane files 400 m north and 300 m south and then files 1200 m upwards then net displacement is

1) 1200 m 2) 1300 m 3) 1400 m 4) 1500 m Answer: 2) 1300 m Solution: displacement in horizontal plane is The net displacement is... View Article

A man goes 10 m towards North, then 20 m towards east then the displacement is

1) 22.5 m 2) 25 m 3) 25.5 m 4) 30 m Answer: 1) 22.5 m Solution: Displacement, = √500 = 22.5... View Article

A particle moving in a straight line covers half the distance with speed of 3 m/s

A particle moving in a straight line covers half the distance with speed of 3 m/s. The other half of the distance is covered in two equal time... View Article

A man is 45 m behind the bus when the bus starts accelerating from rest with acceleration of 2.5 ms^-2. With what minimum velocity should the man start running to catch the bus?

1) 12 ms-1 2) 14 ms-1 3) 15 ms-1 4) 16 ms-1 Answer: 3) 15 ms-1 Solution v2 = u2 + 2as = 0 + 2 x 2.5 x 45 = 225 v... View Article

The area under acceleration-time graph gives

1) distance in travelled 2) change in acceleration 3) force acting 4) change in velocity Answer: 4) change in velocity Solution: a =... View Article

From a balloon rising vertically upwards 5 ms^-1 at stone is thrown up at 10 ms^-1 relative to the balloon. Its velocity w.r.t. ground after 2 s is (assume, g = 10 ms^-2)

1) zero 2) -5 ms-1 3) 10 ms-1 4) 20 ms-1 Answer: 2) -5 ms-1 Solution: From the equation of motion, we have v=u+gt where v is final velocity,... View Article

A bullet moving with a speed of 100 m/s can just penetrate two planks of equal thickness. Then, the number of such planks penetrated by the same bullet when the speed is doubled will be

1) 6 2) 10 3) 4 4) 8 Answer: 4) 8 Solution: Third law of motion, v2 = u2 + 2as here acceleration is negative. Therefore, v2 = u2... View Article

A metro train starts from rest and in 5 s achieves 108 kmh^-1. After that it moves with constant velocity and comes to rest after travelling 45 m with uniform retardation. If total distance travelled is 395 m, find total time of travelling.

1) 12.2 s 2) 15.3 s 3) 9 s 4) 17.2 s Answer: 4) 17.2 s Solution: Given v = 108 km/h =30m/s From first equation of motion v = u + at... View Article

A particle located at x = 0 at time t = 0, starts moving along the positive x–direction with a velocity v that varies as v = α√x. The displacement of the particle varies with time as

1) t2 2) t 3) t1/2 4) t3 Answer: 1) t2 Solution: v = α√x (dx/dt) = α√x x = (α2/4)t2... View Article

An automobile travelling with a speed of 60 kmh^-1, can brake to stop within a distance of 20 m. If the car is going twice as fast, i.e. 120 kmh^-1, the stopping distance will be

1) 20 m 2) 40 m 3) 60 m 4) 80 m Answer: 4) 80 m Solution: From 3rd equaiton of motion, v2=u2+2as 1st case... View Article

A particle moving with a uniform acceleration travels 24 m and 64 m in the first two consecutive interval of 4 s each. Its initial velocity will be

1) 5 ms-1 2) 3 ms-1 3) 4 ms-1 4) 1 ms-1 Answer: 4) 1 ms-1 Solution: Equation of motion, s=ut+1/2at2 When s=24 m, t=4s, we get... View Article