# Physics Essay

1722 WordsApr 22, 20137 Pages
SHM INTERMEDIATE PROBLEMS 7.1 Simple harmonic motion: Definition of simple harmonic motion. a = –k x; T  2 where k is a positive constant. k Displacement-time, velocity-time and acceleration-time graphs for a body in simple harmonic motion. Energy as a function of displacement in simple harmonic motion. Natural and forced vibrations. Mechanical resonance. Graph obtained from experiment. Qualitative description of energy conversion in simple harmonic motion. Including vibrating strings. 1. A student counts his heartbeat and finds that it makes 75 beats in 1 minute. Calculate: (i) the periodic time of his heartbeat, (ii) the frequency. 2. A vibrating string performs 12,000 oscillations in minute. Calculate (i) the frequency and (ii) periodic time for 1oscillation. Draw a simple diagram of a child’s swing as it oscillates between the extreme positions P and Q. On the diagram mark the following: (i) the amplitude, (ii) a point where the velocity is a maximum, (iii) points where the velocity is zero. 3. 4. The diagram shows a simple pendulum oscillating between P and Q. Which of the following statements is correct? a) b) The K.E. of the bob is zero at R. At a point between P and R the bob posses both P.E. and K.E. The P.E. of the bob is a maximum at P. P R Q c) 5. A pendulum is said to perform simple harmonic motion. (a) Define simple harmonic motion. (2 marks) (b) Sketch the displacement time graph for the motion of the pendulum in such a way that when the time, t = 0 the bob is at the centre moving to the right. On the graph mark the amplitude A and the periodic time T. (3 marks) (c) Sketch another graph to show how the velocity and acceleration. of the bob vary with displacemen.t (3 marks) 6. A pendulum is said to perform simple harmonic motion. a) (i) Define simple harmonic motion. (ii) Sketch a