FORCES AND SHAPE
4 marks · NormalA satellite in space is affected by two main forces: the gravitational force of attraction from the Earth, and a small force from the solar wind acting in the opposite direction.
Name the type of force that pulls the satellite towards the Earth.
Explain the nature of gravitational force.
If the force from the solar wind is 0.5 N and the force due to gravity is 100 N, calculate the resultant force on the satellite (assume both act along the same line but in opposite directions).
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(a) Gravitational force
(b) Gravitational force is an attractive force between two masses; it causes objects to be pulled towards one another. In this context, it is the force pulling the satellite towards the Earth.
(c) 99.5 N towards Earth N
Common mistakes: Not subtracting the forces; Confusing direction
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Identifies gravitational force
B2 (b) · 1 mark · States it acts between two masses / attraction
B3 (b) · 1 mark · Relates the effect (pulls towards Earth)
A1 (c) · 1 mark · Correct calculation: 100 N - 0.5 N = 99.5 N
Worked solution
a) The force is called gravitational force.
b) Gravitational force is an attractive force that acts between any two objects with mass. In this case, it pulls the satellite towards the Earth.
c) Resultant force = 100 N (gravity) - 0.5 N (solar wind) = 99.5 N towards Earth.