3 Forces and pressure Answer all questions and show your working out for maximum credit Time allowed : 30 mins Total points available : 32

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1 1 3 Forces and pressure Answer all questions and show your working out for maximum credit Time allowed : 30 mins Total points availale : 32 Core curriculum 1 A icycle pump has its outlet sealed with a tight ruer ung, as shown in Fig a Fig. 1.1 The temperature of the air in the pump is kept constant. The handle of the pump is pushed in so that the piston moves from A to B. Tick the correct ox in each row of the tale elow to show how each quantity varies as the piston is moved. the average speed of the air molecules the frequency with which the air molecules hit the walls and the piston the pressure of the air in the pump greater with piston at A greater with piston at B When the handle is pushed in even further, the ruer ung pops out of the hole. Which two forces are equal just efore the ung pops out? Tick two oxes. friction force etween ung and hole resultant due to forces of air on each side of piston resultant due to forces of air on each side of ung gravitational force on ung same with piston at A or B [3] force of air on walls 2 a Fig. 2.1 shows a uniform rod. [2] [Total: 5] Camridge IGCSE Physics 0625 Paper 2 Q6 Novemer 2009 Fig. 2.1 i Use your rule to find the length of the rod. length =...cm ii On Fig. 2.1, show the position of the centre of mass of the rod using the letter C.

2 2 Fig. 2.2 shows another rod, of the same length as the previous one, ut this rod is thicker at one end. Fig. 2.2 Use your judgement to mark with the letter M approximately where the centre of mass of this rod will e. [2] [Total: 4] Camridge IGCSE Physics 0625 Paper 2 Q1 June A eam is pivoted at its centre. Three forces, F 1, F 2 and F 3, act on the eam as shown in Fig Fig. 3.1 a Which of the forces exert(s) a clockwise moment, an anticlockwise moment? [3] When the eam is released, the right-hand side of the eam starts to go down. Which of the three distances, a, or c, should e decreased in order to alance the eam? Explain your answer. Which distance? Explanation c Fig. 3.2 represents a simple eam-alance with the pivot accurately at its centre. [3] Fig. 3.2

3 3 The person using the eam-alance puts the oject to e weighed in the left-hand pan. He has a selection of standard masses to put in the right-hand pan, ut he finds he cannot exactly alance the eam. His est attempts are masses used effect 10 g, 10 g, 5 g, 2 g, 2 g eam tips down slightly on the left-hand side 20 g, 10 g eam tips down slightly on the right-hand side Estimate the mass of the oject. mass = g [Total: 7] Camridge IGCSE Physics 0625 Paper 2 Q3 June 2008

4 4 Extended curriculum 4 a A man squeezes a pin etween his thum and finger, as shown in Fig Fig. 4.1 The finger exerts a force of 84 N on the pinhead. The pinhead has an area of m 2. i Calculate the pressure exerted y the finger on the pinhead. pressure = [2] ii State the value of the force exerted y the pin on the thum. iii Explain why the pin causes more pain in the man s thum than in his finger. The density of the water in a swimming pool is 1000 kg/m 3. The pool is 3 m deep. i Calculate the pressure of the water at the ottom of the pool. [2] ii pressure = [2] Another pool has the same depth of water, ut has twice the area. State the pressure of the water at the ottom of this pool. pressure = [Total: 8] Camridge IGCSE Physics 0625 Paper 3 Q6 June 2009

5 5 5 A student investigated the stretching of a spring y hanging various weights from it and measuring the corresponding extensions. The results are shown elow. weight/n extension/mm a On Fig. 5.1, plot the points from these results. Do not draw a line through the points yet. c Fig. 5.1 The student appears to have made an error in recording one of the results. Which result is this? Ignoring the incorrect result, draw the est straight line through the remaining points. [2]

6 6 d State and explain whether this spring is oeying Hooke s Law. e Descrie how the graph might e shaped if the student continued to add several more weights to the spring. [2] f The student estimates that if he hangs a 45 N load on the spring, the extension will e 920 mm. Explain why this estimate may e unrealistic. [Total: 8] Camridge IGCSE Physics 0625 Paper 3 Q3 Novemer 2009

7 1 2 Forces and motion Answer all questions and show your working out for maximum credit Time allowed : 30 mins Total points availale : 25 Core curriculum 1 The car in Fig. 1.1 is on a level road. Fig. 1.1 a Calculate the magnitude of the resultant force on the car. Tick the ox elow that descries the motion of the car. travels forward at constant speed resultant force = N travels forward with increasing speed travels forward with decreasing speed travels ackward at constant speed travels ackward with increasing speed travels ackward with decreasing speed remains at rest c d The frictional forces increase to 2000 N when the car is moving. What happens to the car? Suggest two things that might have caused the frictional forces in (c) to increase. 1 2 [2] [Total: 5] Camridge IGCSE Physics 0625 Paper 2 Q3 June 2009

8 2 Extended curriculum 2 a Fig. 2.1 shows a skier descending a hillside. Fig. 2.2 shows the speed/time graph of his motion. Fig. 2.1 Fig. 2.2 i ii How can you tell that the acceleration of the skier is constant during the 8 s shown on the graph? Calculate the acceleration of the skier. acceleration = [2] Another skier starts from rest at the top of the slope. As his speed increases the friction force on the skier increases. i ii State the effect of this increasing friction force on the acceleration. Eventually the speed of the skier ecomes constant. What can e said aout the friction force when the speed is constant? [2]

9 3 iii 1 On the axes of Fig. 2.3, sketch a possile speed/time graph for the motion of the second skier. Fig On your graph, mark with the letter A a region where the acceleration is not constant. Mark with the letter B the region where the speed is constant. [4] 3 Fig. 3.1 shows the speed-time graphs for two falling alls. [Total: 10] Camridge IGCSE Physics 0625 Paper 3 Q3 June 2009 Fig. 3.1 Both alls fall from the same height aove the ground. a Use the graphs to find i the average acceleration of the falling ruer all during the first 3.0 s, acceleration = [2]

10 4 ii the distance fallen y the ruer all during the first 3.0 s, iii the terminal velocity of the plastic all. distance = [2] terminal velocity = Both alls have the same mass ut the volume of the plastic all is much greater than that of the ruer all. Explain, in terms of the forces acting on each all, why the plastic all reaches a terminal velocity ut the ruer all does not. c The ruer all has a mass of 50 g. Calculate the gravitational force acting on the ruer all. [3] force = [2] [Total: 10] Camridge IGCSE Physics 0625 Paper 3 Q1 June 2008

11 1 1 Measurements and units Answer all questions and show your working out for maximum credit Time allowed : 30 mins Total points availale : 28 Core curriculum 1 List five of the seven ase units in the SI system. i ii iii iv v [5] [Total: 5] 2 A schoolteacher is concerned aout the large numer of vehicles passing along the usy road next to the school. He decides to make a measurement to find the numer of vehicles per minute. Using the school clock he notes the following readings. Appearance of clock at eginning of investigation Appearance of clock at end of investigation Vehicles counted travelling left to right = 472 Vehicles counted travelling right to left = 228 a Calculate the time for which the schoolteacher was counting vehicles. counting time = min

12 2 Calculate the total numer of vehicles passing the school per minute. 3 Fig. 3.1 shows a measuring cylinder containing some water. vehicles per minute = [3] [Total: 4] Camridge IGCSE Physics 0625 Paper 2 Q1 June 2009 A student allows 200 drops of water to fall into the water in the measuring cylinder. Fig. 3.2 shows the measuring cylinder after the addition of the drops. Fig. 3.1 Fig. 3.2 a State i the original volume of water in the cylinder, ii the final volume of water in the cylinder. Calculate the volume of water added. cm 3 cm 3 c Calculate the average volume of one of the drops of water. volume added = cm 3 average volume = cm 3 [2] [Total: 4] Camridge IGCSE Physics 0625 Paper 2 Q1 Novemer 2009

13 3 Extended curriculum 4 An engineering machine has a piston which is going up and down approximately 75 times per minute. Descrie carefully how a stopwatch may e used to find accurately the time for one up-and-down cycle of the piston. 5 Fig 5.1 shows part of a measuring instrument. [4] [Total: 4] Camridge IGCSE Physics 0625 Paper 3 Q1 June 2009 Fig. 5.1 a State the name of this instrument. Record the reading shown in Fig c Descrie how you would find the thickness of a sheet of paper used in a magazine...[3] [Total: 5] Camridge IGCSE Physics 0625 Paper 3 Q1 Novemer 2009

14 4 6 The list elow gives the approximate densities of various metals. gold 19 g/cm 3 lead 11 g/cm 3 copper 9 g/cm 3 iron 8 g/cm 3 At an antiques market, a collector uys what is advertised as a small ancient gold statue. When the collector tests it in the laoratory, he finds its mass is 600 g and its volume is 65 cm 3. a In the space elow, descrie how the volume of the statue could e measured. You may draw diagrams if you wish. Use the figures given aove to decide whether the statue was really made of gold. Show your working. [3] Was the statue made of gold? (Tick one ox.) yes no [3] [Total: 6] Camridge IGCSE Physics 0625 Paper 3 Q2 Novemer 2009