USS 2024 SCIPHY Sec 4E PRELIM P2

USS PRELIM 2024/5086/02/Sci Physics Page 1 of 14 UNITY SECONDARY SCHOOL PRELIMINARY EXAMINATION SECONDARY FOUR SCIENCE (PHYSICS, CHEMISTRY) 5086/02 Paper 2 Physics 28 Aug 2024 1 hour 15 minutes Additional Materials: Nil MARKS /65 READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluids. Write your Name, Form Class, Index Number and Teaching Group on the Question Paper and Answer Sheet in the spaces provided. Section A Answer all questions. Write your answers in the spaces provided. Section B Answer one question. Write your answers in the spaces provided. The number of marks is given in brackets [ ] at the end of each question or part question. This paper consists of 14 printed pages, including this cover page. [Turn over Name: Form Class Index No Teaching Group O

USS PRELIM 2024/5086/02/Sci Physics Page 2 of 14 Section A Answer all the questions in the spaces provided. 1 A man makes a parachute jump. Initially, he falls without opening his parachute. Then he opens his parachute and falls to the ground. Fig. 1.1 Fig. 1.1 shows how his speed changes with time after jumping. (a) State the two times in which the man has a non-zero uniform acceleration in between. The man has a non-zero uniform acceleration between .................. s and .................. s [1] (b) State the time at which the man opens his parachute. .........................................................................................................................................[1] (c) Calculate the distance through which the man falls between 50 s and 70 s. distance = .............................. m [3]

USS PRELIM 2024/5086/02/Sci Physics Page 3 of 14 2 A rocket has a mass of 500 kg. The gravitational field strength is 10 N/kg. (a) Calculate the smallest upward force that is needed for the rocket to take off. State the unit. force = .............................. [2] (b) The rocket reaches a speed of 600 m/s in 3.0 s. (i) Calculate the average acceleration of the rocket. State the unit. acceleration = .............................. [2] (ii) Calculate the average force needed to give this acceleration. Assume that the mass of the rocket remains constant. State the unit. force = .............................. [2]

USS PRELIM 2024/5086/02/Sci Physics Page 4 of 14 3 Fig. 3.1 shows a uniform metre rule of mass 120 g suspended at its mid-point from a spring balance which is calibrated in newton (N). Fig. 3.1 An apple, suspended from the metre rule at the 10 cm mark, is balanced by a 100 g mass suspended from the 80 cm mark. Assume g = 10 N/kg. (a) Calculate the mass of the apple. Show your working. mass = .............................. g [3] (b) Explain why the mass of the metre rule play no part in the calculation in (a). ............................................................................................................................................. ............................................................................................................................................. .........................................................................................................................................[2] (c) Determine the reading on the spring balance. reading = .............................. N [3] 10 cm 80 cm 50 cm 100 g

USS PRELIM 2024/5086/02/Sci Physics Page 5 of 14 4 An object of mass 400 g is set into motion so that it slides up a slope with an initial speed of 6 m/s. The object comes to rest after reaching a height of 1.5 m. Calculate, for this object, (a) its initial kinetic store, kinetic store = .............................. J [2] (b) and its gravitational potential store at height of 1.5 m. gravitational potential store = .............................. J [2] (c) Explain the energy pathway that brings about the energy transfer as the object moves up the slope. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. .........................................................................................................................................[3]

USS PRELIM 2024/5086/02/Sci Physics Page 6 of 14 5 Some ice floats inside a container of water. The water temperature decreases. (a) Describe what happens to the internal energy and the kinetic energy of the water as its temperature decreases. ............................................................................................................................................. .........................................................................................................................................[2] (b) By considering the arrangement of the molecules in ice and water, suggest why ice floats on water. ............................................................................................................................................. ............................................................................................................................................. .........................................................................................................................................[2] 6 A sound wave is emitted downwards from a ship. The sound wave is reflected from the seabed and is detected as it arrives back at the ship. See Fig. 6.1 below. Fig. 6.1 The time between emitting the sound wave and detecting it back at the ship is 0.25 s. The seabed is 180 m below the ship. (a) State the nature of sound waves. .........................................................................................................................................[1] (b) Explain how sound waves travel through the sea water. ............................................................................................................................................. ............................................................................................................................................. .........................................................................................................................................[2] (c) Calculate the speed of sound in seawater. speed = ..............................