Duct_Tape_Hour《胶带万能》

...lift a 5,000-pound (2,300 kg) car.

Confirmed

Through small-scale tests, the MythBusters discovered that a single length of duct tape can support up to 70 pounds (32 kg). They then attached the car to a crane with duct tape. The car was lifted successfully, and was left suspended until the tape failed. The MythBusters were quick to point out that the tape itself failed, not its adhesive properties.

...be used to build a fully functional cannon.

Confirmed

The Build Team used 1-inch-thick (25 mm) tiles of duct tape to measure how much strength it could tolerate. Using a small-scale test cannon equipped with a strength gauge, they discovered that the duct tape tile was indeed strong enough to withstand a cannon blast. They then built a duct tape cannon with a 2-inch-thick (51 mm) barrel and compared its performance to that of a conventional steel cannon. Although the range and speed of the duct tape cannon were inferior to the steel one, it successfully fired a cannonball and remained intact.

...be used to construct an entire boat.

Confirmed

The MythBusters built an entire sailboat using 690 square feet (64 m2) of duct tape for the hull and sail. They then took the boat, dubbed the Stuck on You, into San Francisco Bay. The duct tape boat turned out to be fully functional with no sign of failure and, as stated by Adam Savage, "adequately seaworthy", confirming the myth.