Wedge
A roof is not a simple machine. It is a structure built to provide shelter and protection from the elements.
A pin is classified as a type of fastener and not a simple machine. It is often used to secure two materials together.
A tack is a type of wedge, which is a simple machine that is used to push things apart or hold things together.
A projector screen is a type of lever simple machine when it is manually pulled down or rolled up. It can also be considered a pulley simple machine if it is motorized to retract or extend the screen.
If you think about this, you can figure it out. What shape is a shark's tooth? It's a triangle, right? What machine is a triangle shape? The only simple machine that looks like a triangle is a wedge.
Wedge
It is a simple lever mechanism using to hold round objects firmly without slipping, as well as to tighten square, hexagonal nuts or bolts.
A pulley isn't a kind of simple machine, it is a simple machine
A train is not a simple machine.
IT's NOT A SIMPLE MACHINE!
its not a simple machine
It is a simple lever.
Rope is not a simple machine on its own, it's a simple machine on a wheel and axle, then it's a pulley.
a compound machine is a combination of simple machines
lever
lever
It's a simple machine.