WAEC Physics Past Questions & Answers - Page 5

 friction, force that resists the sliding or rolling of one solid object over another.

Examples of friction in our daily life

• Driving of a a vehicle on a surface.
• Applying brakes to stop a moving vehicle.
• Skating.
• Walking on the road.

Hooke's Law states that the extension of a spring is proportional to the load that is applied to it. A variety of materials obey this law as long as the load does not exceed the material's elastic limit.

Archimede's Principle states that a body immersed in a fluid experiences an upthrust equal to the weight of the fluid displaced, and this is fundamental to the equilibrium of a body floating in still water.

When a body floats in a liquid, the weight of the liquid displaced by its immersed part is equal to the total weight of the body. This is the law of floatation.

The Principle of Moments states that when a body is balanced, the total clockwise moment about a point equals the total anticlockwise moment about the same point.

Vernier calipers commonly used in industry provide a precision to 0.01 mm (10 micrometres), or 0.01cm or one thousandth of an inch.

 Usually, it is the total length of the main scale. Vernier calipers, generally, have a range of 300 mm

300 millimeters equal 30.0 centimeters (300mm = 30.0cm).

The viscosity of a material is affected by temperature, pressure, nature of fluid, velocity gradient

Internal energy is affected by factors such as pressure, volume, and temperature.

All of the variables in this list are state functions. Mass, volume, pressure, temperature, density, and entropy are all examples of state functions.

v = ?, u = 0, a = 10, s = 30

V² = U²+2as
V² = 0 + 2 * 10 * 30
V² = 0 + 600
V = √600
V = 24.5m/s 

When water is heated, the density rises and falls steadily, remember the anomalous expansion of water.

Acceleration[a] = \(\frac{[forward - resistive]force}{mass}\)

a = \(\frac{1240-800}{1220}\) → \(\frac{440-800}{1220}\)

a = 0.36m/s\(^2\),  v = 4m/s, s = ?

Second equation of motion:

s is distance
u is initial velocity
v is final velocity
a is acceleration

v\(^2\) = u\(^2\) + 2as

4\(^2\) = 0\(^2\) + 2 * 0.36 * s

16 =  0.72s 

22.2m = s

Refraction occurs when light travels from one medium to another which changes the speed at which the light travels.

This causes light to bend upon incidence with the interface of a new material.

 Angle of refraction is smaller than angle of incidence when light ray travels from rarer medium to denser medium.

I.e  light can either refract towards the normal(when slowing down while crossing the boundary) or away from the normal (when speeding up while crossing the boundary).

When light undergoes refraction, its frequency remains the same.

Radiation is energy that comes from a source and travels through space and may be able to penetrate various materials.

Light, radio, and microwaves are good examples