2018 - JAMB Physics Past Questions and Answers - page 8
For what values of F and θ will the forces shown in the diagram below be in equilibrium.
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
Which of the following phenomena cannot be explained by the molecular theory of matter?
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
The friction which exist between two layers of liquid in relative motion is called.
A particle of mass M initially at rest splits into two. If one of the particles of mass M1 moves with velocity V1 , the second particle moves with velocity
To keep a vehicle moving at a constant speed V requires power P from the engine. The force provided by the engine is
Which of the following is the dimension of pressure
Pressure, P= \(\frac{Force}{Area}\)
P = m × \(\frac{a}{t}\)
= \(\frac{MLT^{−2}}{L × L}\)
= ML\(^{−1}\)T\(^{−2}\)
Palm oil from a bottle flows out more easily after it has been heated because the
Molecules cannot be given energy during the heating and the molecules of oil cannot force each other out
A ball of mass 5.0kg hits a smooth vertical wall normally with a speed of 2ms\(^{-1}\). Determine the magnitude of the resulting impulse
Impulse = Change in momentum
m (v - u)
5 (2.0)
= 5 x 2 = 10.0kgm\(^{-1}\)
= 10.0kgms\(^{-1}\)
The efficiency of energy conversion on the energy flow through a hydroelectric power is?
Efficiency = \(\frac{\text{useful energy output from machine}}{\text{energy input into machine}}\)
= \(\frac{E3}{E2}\)
An object weighs 30N in air and 21N in water. The weight of the object when completely immersed in a liquid of relative density 1.4 is
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