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Two balls are dropped to the ground from different heights. One ball is dropped 2 s after the other but they both strike the ground at the same time. If the first ball takes 5 s to reach the ground, then the difference in initial heights is (take, g= 10 ms^-2)

1) 20 m 2) 80 m 3) 170 m 4) 40 m 5) 160 m Answer: 2) 80 m Solution: s1 = (1/2)gt12 = (10/2) x (5)2 = 125 m s2 = (1/2)gt22 = (10/2)... View Article

A point initially at rest moves along X-axis. Its acceleration varies with time as a = (6t + 5) m s^-2. If it starts from origin, the distance covered in 2 s is

1) 20 m 2) 18 m 3) 16 m 4) 25 m Answer: 2) 18 m Solution: Given, a = (6t + 5) m s-2 Velocity V = ∫adt v = ∫(6t +5)... View Article

A body is moving along a straight line path with constant velocity. At an instant of time the distance travelled by it is s and its displacement is D, then

1) D < s 2) D > s 3) D = s 4) D ≤ s Answer: 3) D = s Solution: In a straight line path with constant velocity, at any instant... View Article

A body starting from rest moves with uniform acceleration. The distance covered by the body in time t is proportional to

1) √t 2) t3/2 3) t2/3 4) t2 Answer: 4) t2 Solution: S = ut + (1/2) at2 Since u = 0 S = (1/2) at2 S ∝ t2... View Article

A bullet emerges from a barrel of length 1.2 m with a speed of 640 ms^-1 . Assuming constant acceleration, the approximate time that spends in the barrel after the gun fired is

1) 4 ms 2) 40 ms 3) 400μs 4) 1s Answer: 1) 4 ms Solution: s = 1.2 m, u = 0 and v = 640 ms-1 From equation of motion 2as =... View Article

The distance travelled by an object along a straight line in time t is given by s = 3 – 4t + 5t² , the initial velocity of the object is

1) 3 units 2) –3 units 3) 4 units 4) –4 units Answer: 4) –4 units Solution: The distance travelled by an object... View Article

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)

1) 6.75 2) 7.25 3) 5.55 4) 8.35 5) 4.75 Answer: 1) 6.75 Solution: V = 45 + 36 = 81 km/h = 81 x (5/18) m/s = (45/2) m/s Therefore, S... View Article

The position coordinates of a particle moving in xy-plane as a function of time t are

The position coordinates of a particle moving in xy–plane as a function of time t are x = 2t2 + 6t +25m and y=t2 + 2t + 2m The speed of... View Article

The distance travelled s by an accelerated particle of mass M is given by the following relation [in MKS units] s = 6t + 3t². The velocity of the particle after 2 s in corresponding unit.

1) 6 2) 12 3) 18 4) 24 Answer: 3) 18 Solution: Given, s = 6t + 3t2 Differentiating w.r.t t v = 6 + 6t Velocity at t = 2s 6 +... View Article

A body moves in a plane, so that the displacement along X and Y–axes is x = 3t² and y = 4t² , then velocity is

1) 15 t2 2) 20 t2 3) 5 t2 4) None of these Answer: 4) None of these Solution: = 10t... View Article

A bullet on penetrating 30 cm into its target loses its velocity by 50%. What additional distance will it penetrate into the target before it comes to rest?

1) 30 cm 2) 20 cm 3) 10 cm 4) 5 cm Answer: 3) 10 cm Solution: S = 30 cm = 30 x 10-2 m and loss in velocity is 50% Equation of motion v2... View Article

A particle is travelling along a straight line OX . The distance x (in metre) of the particle from O at a time t is given by x = 37 + 27t – t³, where t is time in second. The distance of the particle from O when it comes to rest is

1) 81 m 2) 91 m 3) 101 m 4) 111 m Answer: 2) 91 m Solution: The position of the particle is given by the equation x = 37 + 27t... View Article

A person throws balls into air vertically upward in regular intervals of time of 1 s.

A person throws balls into air vertically upward in regular intervals of time of 1 s. The next ball is thrown when the velocity of the ball... View Article

The relation between time t and distance x is t = αx² + βx where α and β are constants. The retardation is

1) -2 αv3 2) 2 βv3 3) 2 αβv3 4) 2 β2v3 Answer: 1) -2 αv3 Solution: t = αx2... View Article

A particle of mass 0.2 kg is moving in one dimension under a force that delivers a constant power 0.5 W to the particle. If the initial speed (in ms^-1) of the particle is zero, then the speed (in ms^-1) after 5 s is

1) 4 2) 2 3) 1 4) 5 Answer: 4) 5 Solution: Kinetic Energy = work = Power x time Therefore, (1/2) mv2 = P x t... View Article

A bullet when first into a target loses half of its velocity after penetrating 20 cm. Further distance of penetration before it comes to rest is

1) 6.66 cm 2) 3.33 cm 3) 12.5 cm 4) 10 cm 5) 5 cm Answer: 1) 6.66 cm Solution: Given, Initial velocity, U=v Final velocity, V=V/2 Distance,... View Article

The density of a solid ball is to be determined in an experiment.

The density of a solid ball is to be determined in an experiment. The diameter of the ball is measured with a screw gauge, whose pitch is 0.5 mm... View Article

A vernier calipers has 1 mm marks on the main scale. It has 20 equal divisions on the Vernier scale which match with 16 main scale divisions. For this Vernier calipers, the least count is

1) 0.02 mm 2) 0.05 mm 3) 0.1 mm 4) 0.2 mm Answer: 4) 0.2 mm Solution: LC = 1 MSD - 1 VSD = 1 mm - 16/20 mm = 0.2 mm... View Article

A car moving at speed 50 km/h one applying brake stops at a distance of 6m. If same car move with the velocity 100 km/h, what distance it cover after applying the brakes.

1) 12 m 2) 18 m 3) 24 m 4) 6 m Answer: 3) 24 mV2 = V02 + 2axV = 0 ⇒ x = -V02/2a x1 = -(50)2/2a x2 = -(100)2/2a (x1/x2) =... View Article

A particle moves with constant acceleration along a straight line starting from rest. The percentage increase in its displacement during the 4th second compared to that in the 3rd is

1) 33% 2) 40% 3) 66% 4) 77% Answer: 2)40% Solution: Snth = U + (1/2)a(2n-1) S3rd = 0 + (1/2)a(2 x 3 -1) S4th = 0 + (1/2)a(2 x 4 -1) Therefore,... View Article