Physics (AS & A Level) · Oct / Nov 2020 · Paper 13 · Question 8

A device for spraying paint consists of a box with its axes horizontal and vertical. One of its vertical faces contains small holes. Paint is fed into the box under pressure via a vertical tube and exits through the holes as fine streams moving horizontally. The paint is ejected at a speed of 2.5 m s⁻¹ through 400 holes, each of area 0.4 mm². The density of the paint is 900 kg m⁻³. What is the horizontal force required to hold the device stationary as it ejects the paint?

1. A0.36 N
2. B0.90 N
3. C2.3 N
4. D900 N

As printed in the paper