HCI 2022 Prelim P1 Guide.pdf

2022 HWA CHONG INSTITUTION (COLLEGE SECTION) C2 © Hwa Chong Institution 1 2022 C2 H2 Physics Prelim Exams Paper 1 Suggested Solutions 1 D 6 B 11 B 16 D 21 C 26 C 2 B 7 A 12 D 17 D 22 A 27 B 3 B 8 C 13 B 18 C 23 C 28 D 4 B 9 B 14 B 19 C 24 A 29 B 5 B 10 A 15 C 20 A 25 D 30 D 1 D 550 GHz = 5.50 x 1011 Hz This corresponds to radiation with wavelength 𝜆 = 3.0 × 108/(5.50 × 1011) ≈ 10-3 m Wavelength of green light is of order of magnitude 10 -7 m. 2 B Conceptual Question. Mean value should be close to the true value, while experimental values should have a large spread. 3 B The gradient of v-t graph give the acceleration, and initial gradient must be ½ of the original. The area under the v-t graph gives the distance between the two train stations, so it must the same for the second train. 4 B By Newton’s first law, the objects can continue at the state of constant velocity. 5 B 𝑀𝑏𝑢𝑏 + 0 = 𝑀𝑏𝑣𝑏 + 𝑀𝑝𝑣𝑝 (5)𝑢𝑏 + 0 = (5)𝑣𝑏 + (1)𝑣𝑝 (1) 𝑢𝑏 − 0 = 𝑣𝑝 − 𝑣𝑏 𝑢𝑏 = 3.33 − 𝑣𝑏 (2) Using (1) and (2) to solve for 𝑢𝑏 = 1.998 𝑚 𝑠−1 6 B Take moments about the pivot. Torque = 5.0(2)(0.5 sin 40º) = 3.2 N m 7 A Consider the vertical component of the tension, and letting the angle that the cord makes with the metal sheet be θ, 2Tsin(θ) = 10 → sin(θ)=0.25 → θ = 14.5º Length of cord required = 2(10/cos(θ)) = 20.7 = 21 cm 8 C Option A and D have the wrong units and can be ruled out immediately. Option B is wrong as vt does not give the total distance traveled as the object is not moving at constant speed. 9 B 2 22 3000 8.02 7897 790060 100a r ms −   = =  =       

2 © Hwa Chong Institution 2 10 A As the Earth is taken to be a uniform sphere, the gravitational potential at any point on the Earth’s surface is the same (as GM R =− , where M is the mass of the Earth and R is the radius of the Earth), hence the gravitational potential energy of the Earth-rocket system is the same whether the rocket is near Equator or near the North Pole. As such the escape speed is the same whether the launch is near the Equator or near the North Pole. 11 B Those who chose C or D did not know that gra vitational potential energy is negative. Those who chose A or C did not know that orbital radius is the sum of the radius of planet and altitude of the satellite. 12 D If both gases are at the same temperature, their average microscopic kinetic energy and root-mean-square speed will be the same. Since the volume of container B is larger than that of A, the gas pressure and density will be smaller in B. 13 B Net work done on the gas = – area enclosed = – area of circle = – = – 3.14 J By