Topic Menu

Cyber-chess a chess instruction site
Questions on Forces

Q8. The drawing below shows an astronaut in space.

He has four small jets attached to his space suit. These jets produce forces on the astronaut in the directions A, B, C and D.

(a) The drawing below shows the size and direction of four forces acting on the astronaut. In which direction, A, B, C or D, will the astronaut move?

The forces to left and right (D and B) cancel each other out.

The up force A is bigger than the down force C. There is therefore a net force of 1N upwards.

Answer: A

1 mark

(b) The drawing below shows the size and direction of four different forces acting on the astronaut. Explain what will happen to the astronaut when the jets produce these four forces.

The forces to left and right (D and B) cancel each other out.

The up force A is the same as the down force C. There is therefore no net force in the vertical direction.

There is no net force acting on him (the forces are balanced).He will therefore not accelerate.

He will continue to move at a steady speed in whatever direction he had been travelling at the time the forces balanced. That initial speed might well have been zero, he would then continue to stay still.

'the forces are equal' is insufficient - must say the 'forces are equal and opposite in direction'

2 marks

(c) The drawing below shows the size and direction of four different forces acting on the astronaut. Draw an arrow on the diagram below to show the direction in which he will move.

See diagram

1 mark

Maximum 4 marks