Questions on Pressure

Q8. The drawing shows an elfin archer. She is holding an arrow and pulling the string of the bow back.

(a) Two horizontal forces act on the arrow.

These are the force exerted by the elf's hand and the force exerted by the string.

The arrow is not moving. The elf pulls the arrow with a force of 150 N.

What is the size of the force exerted by the string on the arrow?

(2 marks)

(b) When the elf lets go of the arrow, it starts to move forward.

Explain why it starts to move.

(1 mark)

(c) The arrow flies across a field and hits an orc.

Two forces act on the arrow while it is in the air.

Air resistance acts in the opposite direction to the movement, and gravity acts downwards.

These two forces cannot balance each other, even when they are the same size.

Why is this?

( 1 mark)

(d) The arrow has a sharp pointed end. When the arrow hits the orc, the sharp point exerts a very large pressure on him.

Why does a sharp pointed end exert a larger pressure than a blunt end?

(2 marks)

Maximum 6 marks