2018 - WAEC Physics Past Questions and Answers - page 1
The S.I unit for sound energy is
Hz
cd
dB
J
The general definition of elastic modulus is
Elastic modulus is the ratio of pressure (stress) applied to a body to the resistance (strain) produced by the body.
= \(\frac{stress}{strain}\)
The diagram above illustrates a simple barometer. Which distance measures the atmospheric pressure?
PQ
QR
RS
QS
The height of the mercury column in a simple barometer is equivalent to the atmospheric pressure.
The property of a body to remain at rest or to continue in uniform motion in a straight line is called
Inertia is the resistance of the object to any change in its motion, including a change in direction. An object will stay still or keep moving at the same speed and in a straight line, unless it is acted upon by an external unbalanced force.
During a training session, two footballers pass a ball repeatedly between each other. The 'to and fro' motion of the ball is not simple harmonic because the
I. Acceleration of the ball is not directed towards a fixed point
II. Restoring force is not directed towards the centre
III. Acceleration of the ball is not directly proportional to the displacement from a fixed point
Which of the statements above are correct?
I and III only
I and II only
II and III only
I, II and III
In Simple Harmonic Motion, the body in motion must have acceleration in a direction opposite to the displacement and the acceleration is directly proportional to displacement and is directed towards its mean position.
A dam is able to hold a large quantity of water because its wall is
thickest at the top
thickest at the middle
thickest at the bottom
of the same thickness throughout
The pressure of the water is greater deeper towards the bottom hence, the dam needs to be thicker at the bottom so it is strong enough to withstand this larger pressure.
A body of mass m moving around a circle of radius r with a uniform speed v experiences a centripetal force F. The work done by the centripetal force on it is
Fv
zero
Fmr
\(\frac{Fr}{m}\)
Work done by centripetal force in a uniform circular motion is 0 Joules.
A block is acted upon by TWO horizontal forces as illustrated in the diagram above. The block accelerates at 1.5\(ms^{-2}\). Calculate the mass of the block.
6kg
9kg
10kg
15kg
Total force exerted on the block = (10 - 1) = 9N
Force = mass x acceleration
9 = m x 1.5
m = 9/1.5 = 6kg
Which of the following quantities are dimensionally independent?
I. Dielectric constant II. Momentum III. Efficiency IV. Refractive index
I and II
II, III and IV
I, II, III and IV
I, III and IV
Efficiency, Dielectric constant and Refractive index are dimensionless quantities.
A body is projected with an initial velocity u at angle \(\theta\) to the horizontal. If \(R_{max}\) is the maximum range of the projectile, what does the relation \(\frac{u^{2}}{R_{max}}\) represent?
The vertical distance covered
Acceleration due to gravity
The horizontal distance covered
The acceleration of the body
\(R_{max} = \frac{u^{2}}{g}\)
\(g = \frac{u^{2}}{R_{max}}\)