1. The drawing shows a very old set of scales. It can be used to check the weights of. pivot

Transcription

1 1. The drawing shows a very old set of scales. It can be used to check the weights of silver coins. pivot pan X pan Y (a) Rema puts a silver coin in pan X. There is nothing in pan Y. In which direction does pan X move? (b) The table shows the weights of five silver coins. Silver coin weight in mn A 106 B 112 C 98 D 112 E 120 Rema puts one coin in each pan of the scales. Which two coins will make the scales balance? Give the letters. and King Charles I School 1

2 I E I E N (c) Coin A is placed in pan X, and coin C is placed in pan Y. In which direction does pan X move?... (d) In another experiment, coin B is placed in pan X, and one of the other coins is placed in pan Y. Pan X goes up. coin B T I S H P E R B C N coin in pan Y pan X T I S H P E R B C pan Y Which coin is in pan Y? Give the letter.. King Charles I School 2

3 (e) Rema knows the weights of the five silver coins in the table. She also has a gold coin. Explain how she could use the coins and the scales to find the approximate weight of the gold coin marks Maximum 6 marks 2. Fran has a balancing game. On each side of the pivot there are nine steel balls. The tray is balanced. A B pivot King Charles I School 3

4 (a) Fran removes one of the steel balls as shown below. A B What will happen to end A?... (b) There are three balls on side A as shown below. Draw three other balls in the correct positions to balance the tray. A B King Charles I School 4

5 (c) Fran puts two steel balls on one side and one brass ball on the other side. The tray is balanced. steel ball brass ball steel ball The mass of each steel ball is 50 g. What is the mass of the brass ball... g (d) The table below gives information about the brass and steel balls. Is it attracted to a magnet? elements in the ball brass no copper and zinc steel yes iron and carbon (i) Which element is not a metal? Tick the correct box. carbon copper iron zinc King Charles I School 5

6 (ii) Look at the elements in the brass ball and the steel ball. Why is steel attracted to a magnet but brass is not?... maximum 5 marks 3. Ali made a cat-flap to fit into a door. door cat-flap bottom of door (a) (i) On the diagram above, draw an arrow to show the direction of the force of the cat s head on the cat-flap. (ii) Add a label to the diagram to show the pivot of the cat-flap. Label it P. King Charles I School 6

7 When the cat has gone through the cat-flap, the weight of the cat-flap makes the flap close. door cat-flap magnets N S bottom of door (b) Ali used two bar magnets to keep the cat-flap closed, so that it does not blow open in the wind. On the diagram above, label both the North and South poles on the magnet in the cat-flap. (c) Friction at the pivot made the cat-flap squeak. What could Ali put on the pivot to make the friction less? Maximum 4 marks King Charles I School 7

8 4. A builder tried to remove a wooden post from the ground by pulling with a rope. hole B 1.6 m hole A 300 N 0.8 m pivot P ground (a) (i) The builder attached a rope to hole A, 0.8 m above the ground. He pulled with a horizontal force of 300 N. Calculate the turning moment about the pivot P. Give the unit marks (ii) He then attached a rope to hole B, 1.6 m above the ground. He pulled with a horizontal force. What force would produce the same turning moment as before?... N King Charles I School 8

9 (b) The post breaks off and falls on the ground as shown. The weight of the broken post is 120 N. The area in contact with the ground is 0.2 m 2. Calculate the pressure of the broken post on the ground. Give the unit marks maximum 5 marks 5. Zena has a model plane attached to a rod as shown below. The plane is balanced by a sliding counterweight. 10 cm 20 cm sliding counterweight pivot rod 5 N W not to scale King Charles I School 9

10 (a) The rod is balanced horizontally. (i) Calculate the turning moment produced by the counterweight about the pivot. Give the unit marks (ii) What is the turning moment produced by the plane about the pivot?... (iii) Calculate the weight, W, of the plane n (b) There is a solar cell on the surface of the model plane. Zena connected the solar cell to the motor of the plane. The plane moved in a circle around the pivot. Part of the path of the plane was in a shadow. What happened to the speed of the plane as it moved from bright light into low light in the shadow?... Explain your answer maximum 5 marks King Charles I School 10

11 6. Alex has a 100 cm ruler pivoted at the centre. She ties a balloon filled with carbon dioxide 16 cm from the pivot, as shown below. The total weight of the balloon and carbon dioxide is 0.06 N. metre ruler 16 cm pivot balloon filled with carbon dioxide gas 0.06 N (a) The ruler becomes unbalanced. Calculate the turning moment the balloon produces about the pivot on the ruler. Give the unit marks King Charles I School 11

12 (b) Alex ties another similar balloon, filled with helium, 48 cm from the pivot. The helium balloon exerts an upward force on the ruler. The ruler is balanced as shown below. balloon filled with helium gas 48 cm metre ruler 16 cm pivot balloon filled with carbon dioxide gas 0.06 N (i) When the ruler is balanced, what turning moment must the helium balloon produce about the pivot?... King Charles I School 12

13 (ii) Calculate the upward force exerted by the helium balloon on the ruler N Maximum 4 marks 7. The diagram shows a simple tool for punching holes in a leather belt. pivot steel peg lightweight handle base hole in base piece of leather force applied not to scale When the handle is pressed down, the steel peg presses down on the piece of leather. If the force is large enough, the peg punches through the leather, making a hole. The diagram below shows the force applied to the handle. pivot 4 cm 10 cm steel peg 50 N not to scale (a) Calculate the moment (turning effect) of the 50 N force applied to the handle. Give the units marks King Charles I School 13

14 (b) This moment makes the steel peg press down on the leather. Calculate the force with which the steel peg presses down on the leather N (c) The next time the punch is used, the steel peg presses down on the leather with a force of 150 N. (i) The area of the end of the steel peg is 0.1 cm 2. What is the pressure of the steel peg on the leather? Give the units marks (ii) The pressure is too small, and the punch does not go through the leather. How could you change the design of the punch to make it work using the same force on the handle? Maximum 6 marks King Charles I School 14