2023 WAEC Physics Theory a. Define each of the following terms used with simple machines: i. Pivot ii.Load iii….

Explanation

a

i. A pivot, often referred to as a fulcrum, is the point or axis around which a simple machine, such as a lever or a seesaw, rotates.

ii. A load is the object or weight that is being moved, lifted, or supported by the machine.

iii. Efficiency refers to how effectively a machine can perform its intended task while minimizing energy loss

b.

i. Given: F = 25.2N, m = 1200kg, u = 0m/s , v = 60km/h = 16.67m/s

               Workdone = ΔK.E = \(K.E_2 - K. E_1\)

               Workdone = \(\frac{1}{2}K.E_2 - \frac{1}{2}K.E_1\)

               Workdone = \(\frac{1}{2}m(v^2 - u^2)\)

               Workdonk  =  \(\frac{1}{2}\times 1200 \times 16.67^2\)   ( since u = 0)

                 Workdone  =   600 x  277.89 = 166733.34J

                    Therefore, Workdone =  \(1.67 \times 10^5\)J

ii.  F = ma → a = \(\frac{F}{m} = \frac{25.2}{1.2 \times10^3} = 0.021ms^2\)

recall, \(v^2 = u^2 +2aS\)

 S = \(\frac{v^2 - u^2}{ 2a} = \frac{16.67^2 - 0^2}{ 2\times 0.021}\)

S = 6616.4m = 6.62km.

c. Absolute zero temperature is the lowest possible temperature that theoretically represents the complete absence of thermal energy while the ice point is the temperature at which water coexists with ice in thermal equilibrium.
- Absolute zero temperature is defined as 0 Kelvin (0 K) or approximately -273.15°C while ice point is typically defined as 0°C at sea level

d. \(\frac{0 - ( - 6)}{ 2 - L} = \frac{ 100 - 0 }{ 15 - 2}\)

\(\frac{ 6}{ 2 - L} = \frac{100 }{ 13}\)

6 x 13 = 100( 2 - L )

78 = 200 - 100L

100L = 200 - 78

100L = 122

L = \(\frac{122}{100}\)  = 1.22cm