n balls each of mass m impinge elastically each second on a surface with velocity v. The average force experienced by the surface will be
2nmv
nmv
4nmv
A monkey of mass 30 kg climbs on a massless rope whose breaking strength is 450 N. The rope will break if the monkey (Take g = 10 m/s2 )
climbs up with a uniform speed of 5 m/s
climbs down with an acceleration 4 m/s2
climbs up with an acceleration 6 m/s2
climbs down with a uniform speed of 5 m/s2
The angle to which a cyclist bends when he covers a circular path of 34.3 m in s is
20°
30°
60°
45°
D.
45°
A gun of mass M fires a bullet of mass m with velocity v. Then, the recoil speed of the gun will be
A solid sphere of radius r made of a material of bulk modulus K is surrounded by a liquid in cyliridrical container. The massless piston of area A floats on the surface of the liquid. If a mass m is placed on a piston to compress the liquid, then the fractional change in the radius of the sphere will be
If a liquid is flowing through a horizontal tube, then = constant. This shows that
If p increases then V also increases
p and V both are constant
If p increases then V decreases
If p decreases then V also decreases
Water wets the walls of its glass container due to the fact that
cohesive force is greater than adhesive force
cohesive force is equal to the adhesive force
adhesive force is greater than the cohesive force
cohesive and adhesive forces form action-reaction pair
A lift is ascending with an acceleration . A simple pendulum suspended from its ceiling oscillates with a period T. The period of oscillation of pendulum when the lift is stationary will be
T
2 T
A stationary source emits a sound moving towards a wall with a velocity u. Speed of sound in air is v. The fractional change in the wavelength of the sound sent and the reflected sound is
Mass of 1 mol of air is 29 x 10-3 kg. The speed of sound at STP will be nearly
332.5 m/s
340 m/s
320 m/s
325 m/s