uhh backpack you idiot..
That would be a backpack.
A knapsack is a bag with shoulder straps that is carried on the back. It is usually made out of canvas o other weatherproof material.
rucksack
You are describing a backpack.
A rucksack or (backpack, haversack, knapsack, packsack) is a bag carried by a strap on your back or shoulder.
a bag carried sometimes by school children
Yes, a laptop can be carried in a carry-on bag when traveling.
It is called a backpack or, less often now, a rucsack.
I carried the bag. Past. I am carrying the bag. Present. I will carry the bag. Future.
A canvas or leather bag for clothes, food or other supplies carried on the back (or over the shoulder)
Yes, razors can be carried on in a carry-on bag as long as they are disposable or have a blade cover.
Baggage is luggage used to hold your clothes etc when you are travelling. A back pack is luggage designed to be carried on your back.