JAMB Physics Past Questions & Answers - Page 71

\(\frac{I}{V}\) = \(\frac{1}{f}\) – \(\frac{1}{u}\)

\(\frac{I}{V}\) = \(\frac{1}{10}\) – \(\frac{1}{20}\)

  = \(\frac{1}{20}\) V

  V = 20cm.

  M = \(\frac{V}{U}\)

  = \(\frac{20}{20}\)

  = 1

Inertia, property of a body by virtue of which it opposes any agency that attempts to put it in motion or, if it is moving, to change the magnitude or direction of its velocity. Inertia is a passive property and does not enable a body to do anything except oppose such active agents as forces and torques. A moving body keeps moving not because of its inertia but only because of the absence of a force to slow it down, change its course, or speed it up.
There are two numerical measures of the inertia of a body: its mass, which governs its resistance to the action of a force, and its moment of inertia about a specified axis, which measures its resistance to the action of a torque about the same axis.

V. R = \(\frac{1}{Sinθ}\)

  m = 20kg

  V.R = \(\frac{1}{Sin 30}\)

  = 2

  Efficiency = 75%

  Load = mg

  = 20 x 10 = 200N

  Efficiency = \(\frac{M.A}{V.R} \times 100\)

  75/100 = \(\frac{M.A}{2}\)

  M .A = \(\frac{75 \times 2}{100}\)

  M. A = 1.5

  Since M. A. = \(\frac{\text{Load}}{\text{Force}}\)

  Force = \(\frac{200}{1.5}\)

  = 133.3N

Momentum = Mass x Velocity
Change in Momentum = Mass x (change in velocity)
Change in Momentum = Mass x (v - u)
Mass = 100g = 0.1kg
U = 2ms\(^{-1}\)
V = 10ms\(^{-1}\)
Change in momentum = m (v − u)
= 0.1 (2 -(- 10))
= 0.1 (12)
= 1.2Ns

The term Adhesive forces refers to the attractive forces between unlike substance