A 210 m long train is moving to North at a speed of 25 m/s. A small bird is flying to South a little above the train with speed 5m/s. The time taken by the bird to cross the train is 1) 6s 2) 7s 3) 9s 4) 10s Answer: 2) 7s Solution: Relative velocity of bird w.r.t train=5 - (-25) =30ms Time taken by the bird to... View Article
The path of a particle moving under the influence of a force fixed in magnitude and direction is 1) Straight line 2) Circle 3) Parabola 4) Ellipse Answer: 1) Straight line Solution: The path of a particle moving under the influence... View Article
A body of 5 kg is moving with a velocity of 20 m/s. If a force of 100 N is applied on it for 10 s in the same direction as its velocity, what will now be the velocity of the body 1) 200 m/s 2) 220 m/s 3) 240 m/s 4) 260 m/s Answer: 2) 220 m/s Solution: F=ma⇒100=5a⇒a=20m/s2 v=u+at=20+20×10=220m/s... View Article
A body A starts from rest with an acceleration a1. After 2 seconds, another body B starts from rest with an acceleration a2. If they travel equal distances in the 5th second, after the start of A, then the ratio a1: a2 is equal to 1) 5 : 9 2) 5 : 7 3) 9 : 5 4) 9 : 7 Answer: 1) 5 : 9 Solution: u = 0 Distance covered in the nth second after starting from rest, S =... View Article
Equation of displacement for any particle is s = 3t3 + 7t2 + 14t + 8m. Its acceleration at time t =1sec is 1) 10 m/s2 2) 16 m/s2 3) 25 m/s2 4) 32 m/s2 Answer: 4) 32 m/s2 Solution: s = 3t3 + 7t2 + 14t + 8m a = d2s/dt2 = 18t + 14... View Article
The average velocity of a body moving with uniform acceleration travelling a distance of 3.06 m is 0.34 ms–1. If the change in velocity of the body is 0.18 ms–1 during this time, its uniform acceleration is 1) 0.01 m/s2 2) 0.02 m/s2 3) 0.03 m/s2 4) 0.04 m/s2 Answer: 2) 0.02 m/s2 Solution: Vaverage = Distance/time = 3.06/0.34 = 9 sec... View Article
Acceleration of a particle changes when 1) Direction of velocity changes 2) Magnitude of velocity changes 3) Both of above 4) Speed changes Answer: 3) Both of above Solution:... View Article
The distance travelled by a particle is proportional to the squares of time, then the particle travels with 1) Uniform acceleration 2) Uniform velocity 3) Increasing acceleration 4) Decreasing velocity Answer: 1) Uniform acceleration Solution:... View Article
The motion of a particle is described by the equation x = a + bt2, where a = 15 cm and b = 3 cm/s2. Its instantaneous velocity at time 3 sec will be 1) 36 cm/sec 2) 18 cm/sec 3) 16 cm/sec 4) 32 cm/sec Answer:Â 2) 18 cm/sec Solution: x = a + bt2 v = dx/dt = 2bt = 2 x 3 x 3 = 18 cm/sec... View Article
If a train travelling at 72 kmph is to be brought to rest in a distance of 200 metres, then its retardation should be 1) 20 ms–2 2) 10 ms–2 3) 2 ms–2 4) 1 ms–2 Answer: 4) 1 ms–2 Solution: Considering the equation v2 = u2 +... View Article
A truck and a car are moving with equal velocity. On applying the brakes both will stop after certain distance, then 1) Truck will cover less distance before rest 2) Car will cover less distance before rest 3) Both will cover equal distance 4) None of the... View Article
If a car at rest accelerates uniformly to a speed of 144 km/hr. in 20 s. Then it covers a distance of 1) 20 m 2) 400 m 3) 1440 m 4) 2880 m Answer: 2) 400 m Solution: Given, u = 0 v = 144 kmph = (144 x 5)/18 = 40 m/s t = 20 sec We... View Article
The position x of a particle with respect to time t along x–axis is given by x = 9t2–t3, where x is in metres and t in second. What will be the position of this particle when it achieves maximum speed along the +xdirection 1) 32 m 2) 54 m 3) 81 m 4) 24 m Answer: 2) 54 m Solution: Given, x = 9t2–t3 v = dx/dt v = 18t - 3t2 v maximum , at dv/dt = 0... View Article
A particle moves along a straight line such that its displacement at any time t is given by S = t3– 6t2 + 3t + 4 metres The velocity when the acceleration is zero is 1) 3 ms–1 2) –12 ms–1 3) 42 ms–1 4)... View Article
An elevator car, whose floor to ceiling distance is equal to 2.7 m, starts ascending with constant acceleration of 1.2 ms–2, 2 sec after the start, a bolt begins falling from the ceiling of the car. The free fall time of the bolt is 1) √0.54 s 2) √6 s 3) 0.7 s 4) 1 s Answer: 3) 0.7 s Solution: Given, the distance between the elevator floor and ceiling,... View Article
A car moving with a speed of 40 km/hr. can be stopped by applying brakes after atleast 2 m. If the same car is moving with a speed of 80 km/hr., what is the minimum stopping distance 1) 8 m 2) 2 m 3) 4 m 4) 6 m Answer: 1) 8 m Solution: Considering the equation of motion v2=u2+2as Ist case... View Article
A car moving with a velocity of 10 m/s can be stopped by the application of constant force F in a distance of 20 m. If the velocity of the car is 30 m/s, it can be stopped by this force in 1) (20/3) 2) 20 m 3) 60 m 4) 180 m Answer: 4) 180 m Solution: Final velocity is zero and the acceleration is negative Using the... View Article
The initial velocity of a body moving along a straight line is 7 m/s. It has a uniform acceleration of 4 m/s2. The distance covered by the body in the 5th second of its motion is 1) 25 m 2) 35 m 3) 50 m 4) 85 m Answer: 1) 25 m Solution: The distance covered by the body in nth second Sn = u+ (a/2) (2n-1)... View Article
What determines the nature of the path followed by the particle 1) Speed 2) Velocity 3) Acceleration 4) Both (b) and (c) Answer: 4) Both (b) and (c) Solution: The nature of the path is determined by... View Article
A car start from rest and accelerates uniformly to a speed of 180 km h–1 in 10 seconds. The distance covered by the car in this time interval is 1) 500 m 2) 250 m 3) 100 m 4) 200 m 5) 150 m Answer: 2) 250 m Solution: u=0, v=180kmh−1=50ms−1 Time taken, t=10s,... View Article
