CIE iGCSE Co-Ordinated Science P1.7 Pressure Exam Style Questions Paper 3

(a)(i) Gravitational attraction
The Sun’s gravitational field provides the centripetal force that keeps the Earth in its nearly circular orbit around the Sun.

(a)(ii) Milky Way
The Sun is one of approximately 100–400 billion stars in the Milky Way galaxy, which is a spiral galaxy about 100,000 light-years in diameter.

(b)(i) Energy = \(I \times V \times t = 96 \times 120 \times 900 = 10,368,000 \text{ J} \approx 10,000,000 \text{ J}\)
The electrical energy transferred is calculated using the formula \(E = IVt\), where current is in amperes, voltage in volts, and time in seconds. The unit of energy is the joule (J).

(b)(ii) Direct current (d.c.) flows in one direction only, whereas alternating current (a.c.) periodically changes direction.
In a direct current circuit, electrons flow continuously in the same direction. In an alternating current circuit, the direction of electron flow reverses periodically (e.g., 50 times per second in mains electricity).

(c)(i) moment = \(300 \times 0.40 = 120 \text{ N m}\)
The moment of a force is calculated using the equation \(\text{moment} = \text{force} \times \text{perpendicular distance from the pivot}\). The unit is newton-metre (N m).

(c)(ii) force = \(20 \times 180 = 3600 \text{ N}\)
Pressure is defined as force per unit area. The force can be calculated by multiplying pressure by area: \(\text{force} = \text{pressure} \times \text{area}\).