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 second is

• 33 %

• 40 %

• 66 %

• 77 %

Particle A moves along X-axis with a uniform velocity of magnitude 10 m/s. Particle B moves with uniform velocity 20 m/s along a direction making an angle of 60° with the positive direction of X-axis as shown in the figure. The relative velocity of B with respect to that of A is

• 10 m/s along X-axis

• $10\sqrt{3}$ m/s along Y-axis (perpendicular to X-axis)

• $10\sqrt{5}$ m/s along the bisection of the velocities of A and B

• 30 m/s along negative X-axis

A cylinder of height h is filled with water and is kept on a block of height h/2. The level of water in the cylinder is kept constant. Four holes numbered 1,2, 3 and 4 are at the side of the cylinder and at heights 0, h/4, h/2 and 3h/4, respectively. When all four holes are opened together, the hole from which water will reach farthest distance on the plane PQ is the hole number

• 1

• 2

• 3

• 4

214.

A ball is thrown vertically upwards. Which of the following  plots represents the speed-time graph of the ball during its flight if the air resistance is not ignored?

• 

• 

• 

• 

An earthquake generates both transverse (S) and longitudinal (P) sound waves in the earth. The speed of S waves is about 4.5 km/s and that of P waves is about 8.0 km/s. A seismograph records P and S waves from an earthquake. The first P wave arrives 4.0 min before the first S wave. The epicentre of the earthquake is located at a distance about

• 25 km

• 250 km

• 2500 km

• 5000 km