GOZO COLLEGE. Half Yearly Examinations for Secondary Schools FORM 3 PHYSICS TIME: 1h 30min. Energy and Work W = Fs E (or W) = Pt. W = mg.

Transcription

1 GOZO COLLEGE Track2 Half Yearly Examinations for Secondary Schools 2013 FORM 3 PHYSICS TIME: 1h 30min Name: Class: Answer all questions. All working must be shown. The use of a calculator is allowed. Where necessary take acceleration due to gravity g = 10m/s 2. You may find some of these equations useful: Energy and Work W = Fs E (or W) = Pt PE = mgh KE = ½ mv 2 Efficiency = power output x 100 power input Weight Moments Density W = mg M = Fs = m/v Number Total Maximum mark Actual mark Actual Mark Total Theory Total Practical Final Mark Maximum Mark Page 1 of 9

2 SECTION A This section carries 40 marks. 1. A student was taking some measurements in a lab. a) Calculate the length of the pencil. Give your answer in metres. [2] b) What is the name of the measuring instrument used to find the mass of the pencil? [1] c) A bottle of olive oil has a mass of 0.97 kg when full and 0.51 kg when empty. What is the mass of the olive oil only? [1] d) What is the name of the measuring instrument used to find the volume of the olive oil? [1] e) Read the volume of the olive oil in the measuring cylinder. [1] f) If water is added to the oil will the water float or sink? Give a reason for your answer. [2] Page 2 of 9

3 2. A car of mass 1000 kg is moving on a road with a forward force of 2000 N. The total resistive force on the car is 1000 N. a) Draw and label four forces acting on the car. [4] b) Calculate weight of car. [1] c) Calculate the resultant force on the car. [2] d) Name a force that is opposing the movement of the car. [1] 3. The diagram shows a TV. a) Complete the following sentence. [1] The TV is designed to transform energy into light and energy. Page 3 of 9

4 b) Straw is a type of renewable energy source known as a bio fuel. The electrical energy is being generated by burning a fossil fuel in the boiler. Fill in the boxes below by writing the main type of energy present. [2] In Generator In the Straw In Boiler In Turbine c) Name one suitable fossil fuel that can be used instead of straw and name an advantage of using this source. [2] _ d) Name one other type of renewable energy source that can be used to produce electricity. [1] _ e) Name two disadvantages that this renewable energy source may have in the production of electricity. [2] Page 4 of 9

5 4. The diagram shows four masses of 100g each hanging from a spring. The pointer is on the 32 cm mark when the masses are suspended. a) What is the weight of the hanging masses in Newtons? [2] b) If the original length of the unstretched spring is 20 cm what is the extension produced by the weights provided? [1] c) Calculate the extension produced by one mass of 100g. [1] d) Calculate the extension produced by eight masses of 100g each. [1] _ e) In reality the extension produced by eight masses is always greater then the value calculated in 4 (d). Give a reason for your answer. [1] f) Complete the following. Hooke s Law states that the produced by a load is always to the force producing it. [2] Page 5 of 9

6 5. Spanish mahogany is a red, lustrous wood. It is prized over Honduras mahogany which is very similar but lighter. Elizabeth bought a Spanish mahogany chest from an antique shop. When she went home she had an argument with her husband Peter about whether it is Spanish or Honduras mahogany. She searched the internet and obtained the following data. a) A piece of Honduras mahogany has a volume of m 3 and a mass of 349 kg. Calculate its density. [2] b) Another piece of Spanish mahogany has a mass of 250 kg and a volume of m 3. Calculate its density. [2] c) Elizabeth took a loose rectangular piece of wood from her chest to determine its density. Calculate its volume if the piece of wood length was 0.50 m, width 0.05 m and height 0.05 m. Give your answer in m 3. [2] d) She found that her sample mass (in question 5c ) was 1.06 kg. Find its density and determine whether the chest she bought is Spanish or Honduras Mahogany? [2] Page 6 of 9

7 SECTION B This Section carries 45 marks. 6. The diagram shows a cable car used to take skiers to the top of a mountain. The total mass of the cable car and skiers is 7500 kg a) Calculate the weight of the cable car and skiers. [2] b) Calculate the work done to lift the cable car and skiers a vertical height of 800 m. [3] _ c) If it takes 420 s to lift the cable car and skiers, calculate the power. [3] d) Do you expect the efficiency of cable car motor to be ( 100 %, 60 %, 15 %). Underline the correct answer. [2] e) The diagram shows a skier who is moving down a mountain 800 m high. If skier mass is 70 kg calculate the potential energy at the top of the mountain. [3] f) What is the Kinetic energy of the skier at the end of ski slope? [2] Page 7 of 9

8 7. A student was carrying an experiment to investigate how the kinetic energy varies as the height fallen by an object increases. The student drops a piece of plasticene of mass 50 g from the same height and the velocity at different heights is read each time by means of a data logger. a) Write down the name of two pieces of apparatus in the above diagram.. [2] b) Three precautions necessary to obtain good readings are : (underline correct answer) [3] Take ( one reading, many readings ), Read ruler ( at eye level, looking from above ), drop plasticene ( vertically, at an angle ) Height of light gate from the ground (m) Velocity (m/s) Kinetic Energy KE =½ m v ² (J) c) Draw a graph of Kinetic energy on the y axis against Height of light gate on x axis. [6] d) The kinetic energy of the plasticene ( increases / decreases ) as the height fallen increases?[2] e) The law of conservation of energy states that energy cannot be nor destroyed but is changed from one form to another. [2] Page 8 of 9

9 8. The following diagram shows Maria and Paul on a seesaw. Maria whose weight is 500 N is at a distance of 1.2 m away from the pivot P while Paul is 0.8 m away from pivot. a) Calculate the moment of Maria about the pivot. [2] b) At equilibrium clockwise moments about point P are ( equal, greater, smaller ) than anticlockwise moments. (underline correct answer) [2] c) What is Paul s moment? [2] d) Calculate the weight of Paul. [3] e) Calculate Paul s mass. [2] f) What is the total downward force acting on the seasaw. [2] g) What is the total upward force produced by seesaw. [2] Page 9 of 9