A balloon of volume 100m³ and mass 2kg is filled with helium of density 0.18kg/m³ at ground level. The surrounding air has a density of 1.28kg/m³. Calculate the maximum mass which the balloon can lift off the ground.

Mechanical pumps cannot

A solid weighs 6.4N in air, 5.4N in water and 5.6N in kerosene. Calculate the relative density of kerosene.

A cube of glass of 5cm side and mass 306g has a cavity inside it. If the density of glass is 2.55g/cm³, what is the volume of the cavity?

Which of the following factors influence the rate of flow of water through a pipe to houses?
I. the material of the pipe
II. the diameter of the pipe
III. the viscosity of the water

A hose ejects water at a speed of 15cm/s through a hole of area 75cm². If the water strikes a wall normally, calculate the force on the wall. (Assuming that the velocity of water after striking the wall is zero and density of water = 1000kg/m³).

The hatch door of a submarine has an area of 0.5m². The specific gravity of sea water is 1.03, assume that g = 10m/s² and neglect the atmospheric pressure, the force exerted by the sea water on the hatch door at the depth of 200m is

An open tank holds water 1.25m deep. If a small hole of cross-sectional area 3cm² is made at the bottom of the tank, calculate the mass of water per second initially flowing at the hole (g = 10m/s², density of water = 1000kg/m³)

At what depth below the sea-level would one experience a change of pressure equal to one atmosphere? (density of sea water = 1013kg/m³; one atm = 101,000N/m²;
g = 10m/s²)

Which of the following is suitable to use an altimeter?

A liquid of mass 1000kg fills a rectangular tank of length 2m. If the tank is 4m high, what is the pressure at the middle of the tank?

40cm³ of liquid P is mixed with 60cm³ of another liquid Q. If the density of P and Q are 1.00kg/m³ and 1.6kg/m³ respectively, what is the density of the mixture?

If a spherical metal bob of radius 3cm is fully immersed in a cylinder containing water and the water level rises by 1cm. What is the radius of the cylinder?

Which of the following cannot be correctly explained using the concept of surface tension?

Mercury is suitable as a barometric fluid because it

A man on a bench will exert the greatest pressure on the bench when he

A spherical metal ball falling through a viscous liquid is acted upon by the 
I. weight of the ball
II. viscous force of the liquid on the ball
III. upthrust of the liquid on the ball

When the temperature of a liquid is increased, its surface tension.

Calculate the pressure on Radeyah's thumb when she exerts a force of 20N and the top of the pin is square, the length of each side being 10mm
0.2N/mm²

In which of the following is surface tension important?

When a paint brush is removed from clean water, the bristles of the brush are pulled together because of

Air was pumped out of a sealed can and the can collapsed. 
Which of these statements is the best explanation for this?

A cube of sides 0.1m hangs freely from a string. What is the upthrust on the cube when totally immersed in water?

A body whose mass is 2kg has a volume of 500cm³ just floats when completely immersed in a liquid. Calculate the density of the liquid

A thin hydrometer floats stationary in water at a temperature of about 20ºc. If the water is gradually cooled to 0ºc, their hydrometer will.