What lever are paper-cut scissors?

Question 1: Are paper-cutting scissors levers? What's your reason? Scissors are usually equal-arm levers. Because of its universality, the handshake position is generally equal to the blade position, but when in use, the blade root can be used to make a labor-saving lever. Scissors for cutting fish in the kitchen are labor-saving levers with long handshakes and short blades; Scissors for haircut and cloth cutting have long blades and do not need much effort. They are laborious levers. Specifically, look at the length relationship between the blade and the handshake: the blade is a laborious lever, the blade is a labor-saving lever, and the same length is an equal arm lever.

Question 2: Among the following levers, () A. Scissors cut paper B. Screwdrivers open bottles C. Tweezers ... A. Scissors as shown in the figure have a long handle and a short blade, so in use, the power arm is larger than the resistance arm, which is a labor-saving lever, so A does not meet the meaning of the question; BD, in order to save energy in life, we use a screwdriver to open bottles and pliers to cut wires. When using them, both are power arms larger than the resistance arm, so they are labor-saving levers, so B and D do not meet the meaning of the question; C. in the process of using tweezers, the resistance arm is larger than the power arm, which can save the distance and belongs to the laborious lever, so C meets the meaning of the question.

Question 3: Why is it easier to cut paper with scissors than with a knife? (Hint: Lever principle) The power arm of scissors is longer than the resistance arm.

Question 4: The mechanical efficiency of scissors paper-cutting as shown in the figure is 80%, which means () a. If the resistance acting on scissors is 1N, the power is 0.8NB ... If AB and scissors can be regarded as a lever, according to the balance condition of lever F 1L 1=F2L2, we must know the strength or resistance. C, the purpose of using scissors is paper-cutting, so the work done by paper-cutting is useful, and the mechanical efficiency is 80%. If the power supply is 1J and the paper-cutting is 0.8J, the C option is correct; D. The useful work done by scissors in the paper-cutting process is uncertain, so it is impossible to determine the work done by scissors in1s. Option d is wrong, choose C.

Question 5: Are paper-cutting scissors levers? What's your reason? Scissors are usually equal-arm levers. Because of its universality, the handshake position is generally equal to the blade position, but when in use, the blade root can be used to make a labor-saving lever. Scissors for cutting fish in the kitchen are labor-saving levers with long handshakes and short blades; Scissors for haircut and cloth cutting have long blades and do not need much effort. They are laborious levers. Specifically, look at the length relationship between the blade and the handshake: the blade is a laborious lever, the blade is a labor-saving lever, and the same length is an equal arm lever.

Question 6: Among the following levers, () A. Scissors cut paper B. Screwdrivers open bottles C. Tweezers ... A. Scissors as shown in the figure have a long handle and a short blade, so in use, the power arm is larger than the resistance arm, which is a labor-saving lever, so A does not meet the meaning of the question; BD, in order to save energy in life, we use a screwdriver to open bottles and pliers to cut wires. When using them, both are power arms larger than the resistance arm, so they are labor-saving levers, so B and D do not meet the meaning of the question; C. in the process of using tweezers, the resistance arm is larger than the power arm, which can save the distance and belongs to the laborious lever, so C meets the meaning of the question.

Question 7: Among the levers listed in the figure below, () A. Iron scissors B. Barber scissors C. Branch scissors D. Steel wire A. During the use of iron scissors, the power arm is larger than the resistance arm, which is a labor-saving lever; B, the power arm is smaller than the resistance arm, and the scissors are laborious levers when used; C, in the process of using the branch shears, the power arm is larger than the resistance arm and is a labor-saving lever; D. During the use of wire cutters, the power arm is larger than the resistance arm, which is a labor-saving lever. So I chose B.