Ice cubes are added to a glass of warm water. The glass and water are cooled by
- A. conduction only
- B. convection only
- C. conduction and convection
- D. convection and radiation
Which of the following consists entirely of vector quantities?
- A. Velocity, displacement and reaction
- B. Tension, magnetic flux and mass
- C. Displacement, impulse and power
- D. Work, pressure and moment
The efficiency of a machine is always less than 100% because the
- A. work output is always greater than the work input
- B. load lifted is always greater than the effort applied
- C. effort applied is always greater than the load lifted
- D. velocity ratio is always greater than the mechanical advantage
I. The earth is not spherical but elliptical in shape
II. Variation in latitude and longitude
III. Rotation of the earth on its axis
IV. Variation in the density of the earth
On which combination of the above does the weight of an object vary on the earth’s surface?
- A. I, II, III and IV
- B. III and IV only
- C. I, II and III only
- D. I and II only
The resultant of two forces acting on an object is maximum if the angle between them is
- A. 45°
- B. 0°
- C. 90°
- D. 180°
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?
- A. 12cm
- B. 1cm
- C. 3cm
- D. 6cm
A stone of mass 1kg is dropped from a height of 10m above the ground and falls freely under gravity. Its kinetic energy 5m above the ground is then equal to
- A. its kinetic energy on the ground
- B. twice its initial potential energy
- C. its initial potential energy
- D. half its initial potential energy
The height at which the atmosphere ceases to exist is about 80km. If the atmospheric pressure on the ground level is 760mmHg, the pressure at a height of 20km above the ground level is
- A. 380mmHg
- B. 570mmHg
- C. 190mmHg
- D. 480mmHg