CBSE
Multiple Choice QuestionsAn 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
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?
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
m/s along Y-axis (perpendicular to X-axis)
m/s along the bisection of the velocities of A and B
30 m/s along negative X-axis
From the top of a tower, 80 m high from the ground, a stone is thrown in the horizontal direction with a velocity of 8 ms-1 . The stone reaches the ground after a time 't' and falls at a distance of 'd' from the foot of the tower. Assuming g = 10 m/s2, the time t and distance d are given respectively by
6 s, 64 m
6 s, 48 m
4 s, 32 m
4 s, 16 m
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
