Why is a match stick lighted on rubbing it on the rough surface provided on the side of the match box?

What shape is A match box

Look at the match sticks patterns of squares. The squares are not separate. Two neighbouring square have a common match stick. Observe the patterns and find the rule take gives the number of match sticks in term of numbr of squares.

The rear side of a truck is open and a box of 40 kg mass is placed 5 m away from the open end as shown. The coefficient of friction between the box and the surface below its is 0.15. On a straight road, the truck starts from rest and accelerates with 2 ms^-2 . At what distance from the starting point does the box fall off the truck ?/ (Ignore the size of the box).

The rear side of a truck is open and a box of 40 kg mass is placed 5 m away from the open end as shown in Fig. 5.22. The coeffcient of friction between the box and the surface below it is 0.15. On a straight road, the truck starts from rest and accelerates with 2 m s^-2 . At what distance from the starting point does the box fall off the truck? (Ignore the size of the box).