2018 - JAMB Physics Past Questions and Answers - page 5

Commission means a task or mission to accomplish.

Take note of the double ‘s’ and the double ‘m’. All other options are wrongly spelt

A vernier scale is a visual aid to take an accurate measurement reading between two graduation markings on a linear scale by using mechanical interpolation; thereby increasing resolution and reducing measurement

Mechanical Advantage, M.A Velocity Ration (V.R) × Efficiency

M.A  = 5 × 0.72

M.A  = 3.6

When an atom gains or loses an electron it becomes an ion. If atom that gains a negative electron, it becomes a negative ion but if it loses an electron it becomes a positive ion

Initial momentum = (0.8) × (5)

 = 4.0kgms${}^{-1}$

  Final momentum

  = (0.8) × (– 5)

 = – 4.0kgms${}^{-1}$

  Impulse on ball

  = Change in momentum

 = 4.0 – (– 4.0)

  = 8.0.0kgms${}^{-1}$

Cohesion is the inter-molecular attractive force acting between two adjacent portions of a substance, particularly of a solid or liquid. It is this force that holds a piece of matter together

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 (10 − 2)

= 0.1 (8)

= 0.8Ns

V. R = $\frac{1}{Sin\theta }$

  m = 20kg

  V.R = $\frac{1}{Sin30}$

  = 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 = 75 x $\frac{2}{100}$

  M. A = 1.5

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

  Force = 1.5 x 200

  = 87 N

Inertia is the 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.

$\frac{I}{V}$ = $\frac{1}{f}$ – $\frac{1}{u}$

$\frac{I}{V}$ = $\frac{1}{10}$ – $\frac{1}{20}$

  = $\frac{1}{20}$ V

  V = 20cm.

  M = $\frac{V}{U}$

  = $\frac{20}{20}$

  = 1