Correct Answer: C. was not sincere at all

Correct Answer: B. social interest

Explanation

The Britain colonized the Africa not for social interest but economic interest especially

Explanation

(a)(i) A machine is a device used to overcome a load at one end by the application of an effort at another end. Examples of simple machine include the screw jack, can opener, pulley system. (ii) M.A. is the ratio of the load (L) to the Effort (E).

\(M.A = \frac{Load}{Effort}\)

V.R. is the ratio of the distance moved by the effort tc the distarice moved by the load (at the same time).

\(V.R = \frac{\text{distance moved by effort}}{\text{distance moved by load}}\)

Efficiency (E) is the ratio of the useful work done by the machine (work output) to the total work put into the machine (work input).

\(Efficiency = \frac{\text{work done on load}}{\text{work done by effort}} \times 100%\)

\(Efficiency = \frac{M.A}{V.R} \times 100%\);

\(Work = Force \times Distance\)

\(Efficiency = \frac{\text{work output}}{\text{work input}} \)

= \(\frac{Load \times \text{distance moved by load}}{Effort \times \text{distance moved by effort}}\)

= \(M.A \times \frac{1}{V.R} \times 100%\)

(b) The efficiency of a simple machine is not 100% because of the work done in overcoming friction.

(c) length of tommy bar. L = 70cm = 0.7m; Pitch = 4.4mm = 0.0044m.

(i) \(V.R = \frac{2\pi L}{pitch} = \frac{2 \pi \times 0.7}{0.0044}\)

= \(2 \times \frac{22}{7} \times \frac{0.7}{44 \times 10^{-4}}\)

\(V.R = 1000\)

(ii) \(Efficiency = \frac{M.A}{V.R} \times 100%\)

\(\frac{80}{100} = \frac{M.A}{1000} \implies M.A = 800\)

(iii) \(M.A = \frac{Load}{Effort}\)

\(Effort = \frac{8000 \times 10}{800} = 100N\)

(iv) Work done = \(\frac{load \times \text{distance moved by load}}{effort \times \text{distance moved by effort}}\)

= \(\frac{8000 \times 10 \times 0.2}{0.8} = 20,000J\)

Correct Answer: D. Protagonist

Explanation

A protagonist (from Ancient Greek ????????????? (protagonistes), meaning 'one who plays the first part, chief actor') is the leading character of a story. Theprotagonist is at the center of the story, makes the key decisions, and experiences the consequences of those decisions.

Correct Answer: D. most intense point of the conflict

Correct Answer: C. varying lengths of day and night

Correct Answer: D) vending machine

Explanation

Option A: A franking machine is used to stamp and post mail, so it does not directly enable sales without a sales attendant.

Option B: A telex machine is used for sending written messages over long distances, but it also does not directly enable sales without a sales attendant.

Option C: A fax machine is used to send and receive documents electronically, but it also does not directly enable sales without a sales attendant.

Option D: A vending machine is a machine that dispenses items such as snacks or drinks when money is inserted. This option allows for sales to happen without a sales attendant because customers can directly purchase items from the vending machine without the need for a person to handle the transaction.

Therefore, the correct answer is Option D: vending machine

Correct Answer: A. hygrometer

Explanation

The instrument used to measure relative humidity is called hygrometer. The hygrometer consist of wet and dry bulb thermometer placed side by side in the sterensonscreen.

Correct Answer: A. sky

Correct Answer: D. eight