NYJC_EJC 2026 Frames of Reference Tutorial

9814 H3 Physics Frames of Reference - Tutorial 1 FRAMES OF REFERENCE (NON-RELATIVISTIC) 1 A car travels due east with a speed of 15.0 m s-1. Raindrops are falling at a constant speed vertically with respect to the Earth. The traces of the rain on the side windows of the car make an angle of 60.0° with the vertical. Determine the velocity of the raindrop with respect to (a) the car. (b) the Earth. 2 A bolt drops from the ceiling of a moving train car that is accelerating northward at a rate of 2.50 m s-2. (a) What is the acceleration of the bolt relative to the Earth? (b) What is the acceleration of the bolt relative to the train? (c) Describe the trajectory of the bolt as seen by an observer inside the train car. (d) Describe the trajectory of the bolt as seen by an observer fixed on the Earth. 3 A uniform piece of steel sheet is shaped as below. Find the x and y coordinates of the centre of mass of the piece. 4 A stone is dropped at t = 0. A second stone, with twice the mass of the first, is dropped from the same point at t = 100 ms. (a) How far below the release point is the center of mass of the 2 stones at t = 300 ms? (Assume neither stone has yet reached the ground.) (b) How fast is the center of mass of the two-stone system moving at that time?

9814 H3 Physics Frames of Reference - Tutorial 2 5 The figure shows a simple model of the structure of a water molecule. The separation between molecules d is 9.57 × 10-11 m. Each hydrogen atom has mass 1.0 u, and the oxygen atom has mass 16.0 u. Determine the position of the centre of mass. 6 Car A of mass 1800 kg and car B of mass 1500 kg are at rest on a 22 000 kg stationary flatcar. Assuming that the length the car is negligible compared to the length of the flatcar , determine the velocity of the flatcar when car A and B are moving at constant speeds of 2.5 m s-1 and 1.0 m s-1 relative to the flatcar respectively. 7 A 2.0 kg model rocket is launched vertically. When it reaches an altitude of 70 m with a speed of 30 m s-1, it explodes into two parts mA and mB of masses 0.70 kg and 1.30 kg respectively. 6.0 s after the explosion, mass m A is observed to strike the ground 80 m west of the launch point. Determine the position of mass mB at that time.

9814 H3 Physics Frames of Reference - Tutorial 3 8 Bodies X and Y of mass 2.0 kg and 3.0 kg respectively approach each other with speeds 8.0 m s−1 and 4.0 m s−1 respectively. Given that the two bodies collide head-on elastically, determine their speeds after the collision. 8.0 m s −1 4.0 m s −1 2.0 kg 3.0 kg