2018 - JAMB Physics Past Questions and Answers - page 8

Resolving the vertical component of the force, 40cosθ = 20, θ = 60\(^o\)

Resolving the horizontal component of the force, f = 40sinθ = 40sin60\(^o\)

  = 40(\(\frac{\sqrt{3}}{2}\))

  = 20√3 N

Conduction: the flow of internal energy from a region of higher temperature to lower temperature

Convection: heat transfer due to bulk movement of molecules within fluids

Expansion: the action of becoming larger or more extensive

Viscosity, resistance of a fluid (liquid or gas) to a change in shape, or movement of neighbouring portions relative to one another. Viscosity denotes opposition to flow. The reciprocal of the viscosity is called the fluidity, a measure of the ease of flow. Molasses, for example, has a greater viscosity than water.

~ Britannica - viscosity

P = F × \(\frac{S}{1}\)

P = F x V

F = (\frac{P}{V})

Pressure, P= \(\frac{Force}{Area}\)

  P = m × \(\frac{a}{t}\)

  = \(\frac{MLT^{−2}}{L × L}\)

  = ML\(^{−1}\)T\(^{−2}\)

Molecules cannot be given energy during the heating and the molecules of oil cannot force each other out

Impulse = Change in momentum

  m (v - u)

  5 (2.0)

  = 5 x 2 = 10.0kgm\(^{-1}\)

  = 10.0kgms\(^{-1}\)

Efficiency = \(\frac{\text{useful energy output from machine}}{\text{energy input into machine}}\)

= \(\frac{E3}{E2}\)

Weight of water displaced = upthrust = 30 - 21 = 9N

  Mass of water displaced = \(\frac{9}{10}\) = 0.9kg

  Volume of object = 9 × 10\(^{-4}\)m\(^3\)

  = (9 × 10\(^{-4}\)) (1.4 ×103)

 = 1.26kg = 12N

  30 - 12.6 = 17.4N