A body falls freely for 10 s. Its average velocity during this journey is (Take, g = 10 ms^-2)

• 100 ms^-1

• 10 ms^-1

• 50 ms^-1

• 5 ms^-1

Three projectiles A, B and C are projected at an angle of 30°, 45°, 60° respectively. If R_A, R_B and R_C are ranges of A, B and C respectively, then (velocity of projection is same for A, B and C)

• R_A = R_B = R_C

• R_A = R_C > R_B

• R_A < R_B < R_C

• R_A = R_C < R_B

The component ofa vector r along X-axis will have a maximum value, if

• r is along positive X-axis

• r is along positive Y-axis

• r is along negative Y-axis

• r makes an angle of 45° with the X-axis

Maximum acceleration of the train in which a 50 kg box lying on its floor will remain stationary (Given, coefficient of static friction between the box and the train's floor is 0.3 and g = 10 ms^-2)

• 5.0 ms^-2

• 3.0 ms^-2

• 1.5 ms^-2

• 15 ms^-2

A 12 kg bomb at rest explodes into two pieces of 4 kg and 8 kg. If the momentum of 4 kg piece is 20 Ns, the kinetic energy of the 8 kg piece is 

• 25 J

• 20 J

• 50 J

• 40 J

6.

Which of the points is likely position of the centre of mass of the system shown in the figure ?

                      

• A

• D

• B

• C

Three bodies a ring (R), a solid cylinder (C) and a solid sphere (S) having same mass and same radius roll down the inclined plane without slipping. They start from rest, if v_R, v_C and v_S are velocities of respective bodies on reaching the bottom of the plane, then

• v_R = v_C = v_S

• v_R > v_C > v_S

• v_R < v_C < v_S

• v_R = v_C > v_S

Variation of acceleration due to gravity (g) with distance x from the centre of the Earth is best represented by (R → Radius of the Earth)

A spring is stretched by applying a load to its free end. The strain produced in the spring is

• volumetric

• shear

• longitudinal and shear

• longitudinal

An ideal fluid flows through a pipe of circular cross-section with diameters 5 cm and 10 cm as shown in the figure. The ratio of velocities of fluid at A and B is

• 4 : 1

• 1 : 4

• 2 : 1

• 1 : 2