CBSE
Multiple Choice QuestionsA ball of mass 10 g moving with acceleration of 20 m/s2 is hit by a force which acts on it for 0.1 sec. The impulsive force is
1.2Ns
0.3Ns
0.1Ns
0.5Ns
A police jeep is chasing with velocity of 45 km/h. A thief in another jeep moving with velocity 153 km/h. Police fires a bullet with muzzle velocity of 180 m/s. The velocity it will strike the car of the thief is
150 m/s
27 m/s
450 m/s
250 m/s
Two similar charges having mass m and 2m are placed in an electric field. The ratio of their kinetic energy is :
4:1
1:1
2:1
1:2
A car starts from rest, moves with an acceleration a and then decelerates at a constant rate b for sometimes to come to rest. If the total time taken is t. The maximum velocity of car is given by :
A river is flowing from west to east with a speed of 5 m/min. A man can swim in still water with a velocity 10 m/min. In which direction should the man swim so, as to take the shortest possible path to go to the south?
30o east of south
60o east of south
60o west of south
30o west of north
Two boys are standing at the ends A and B of a ground, where AB = a. The boy at B starts running in a direction perpendicular to AB with velocity v1 The boy at A starts running simultaneously with velocity v and catches the other boy in a time t, where t is
A ball is thrown vertically upward. It has a speed of 10 m/s when it has reached one-half of its maximum height. How high does the ball rise? ( Take, g = 10 m/s2 )
15 m
10 m
20 m
5 m
A car moves from X to Y with a uniform speed vu and returns to Y with a uniform speed vd The average speed for this round trip is
A particle moves along a straight line OX. At a time t (in second) the distance x ( in metre ) of the particle from O is given by x = 40 + 12 t - t3 . How long would the particle travel before coming to rest?
24 m
40 m
56 m
16 m
A small disc of radius 2 cm is cut from a disc of radius 6 cm. If the distance between their centres is 3.2 cm, what is the shift in the centre of mass of the disc?
0.4 cm
2.4 cm
1.8 cm
1.2 cm
