Physics playground

 1.A student says that he had applied a force F=- k√x on a particle and the particle moved in simple harmonic motion. He refuses to tell whether k is a constant or not. Assume that he has worked only with positive x and no other force acted on the particle. (a) As x increases k increases. (b) As x increases k decreases. (c) As x increases k remains constant. (d) The motion cannot be simple harmonic.  2. The time period of a particle in simple harmonic motion is equal to the time between consecutive appearances of the particle at a particular point in its motion. This point is (b) an extreme position (a) the mean position (c) between the mean position and the positive extreme (d) between the mean position and the negative. extreme.  3. The time period of a particle in simple harmonic motion is equal to the smallest time between the particle acquiring a particular velocity v. The value of u is  (a) Vmax  (b)0  (c) between 0 and Vmas   (d) between 0 ...

1. Find the acceleration of the moon with respect to the earth from the following data. Distance between the earth and the moon = 3.85 × 10 ³ km and the time taken by the moon to complete one revolution around the earth = 27.3 days Solution Distance between Earth and moon  r=3.85x10⁵km = 3.85x10⁸m T=27.3days=24x3600 x (27.3)sec = 2.36 x 10⁶sec v = 2πr/T = 2x3.14 x3.85x10⁸/2.36 x 10⁶ =1035.42m/sec a= v²/r = (1024.42)²/3.85x10⁸ ⁼ 0.00273msec⁻² = 2.73 x 10⁻³m/sec⁻² 2.Find the acceleration of a particle placed on the surface of the earth at the equator due to earth's rotation. The diameter of earth 12800 km and it takes 24 hours for the earth to complete one revolution about its axis.  SOLUTION Diameter of earth = 12800km Radius R= 6400km = 64 x 10⁵m a= 2πR/T = 2x3.14 x 64 x 10⁵/  24 x3600 msec⁻¹ =465.185msec⁻¹ a V²/R = (46.5185)/64x10⁵ =0.0338m/sec² A particle moves in a circle of radius 10 cm at a speed given by v 2.0 t where u is in cm/s and t in seconds. = (a) Find the ra...

SPEED, DISPLACEMENT, VELOCITY, ACCELERATION Velocity time graph Motion under gravity In this blog I will be solving multiple questions with answers on speed , displacement, velocity and acceleration Speed SPEED is defined as the rate of change of distance with respect to time. It is also know as average speed.      Speed is a scalar quantity. It has a magnitude but no direction. The unit of speed is meter per second (m/s) Average speed = ∆distance/∆time =  Final distance-initial distance/final time-initial time. Average speed = distance/time =s/t QUESTIONS AND ANSWERS ON SPEED 1.1A man walks a distance of 58km in 2hours calculates his average speed. Average speed =distance/time =58km/2hrs  X 1000m/3600s X hrs/km =8.06m/s Hint: 1km= 1000meters 1hours =3600seconds 1hours=60minutes 1minutes=60seconds 1.2 A taxi driver with a speed of 20km/hrs saw a goat on a highway and applied a break. It came to rest after 10seconds. calculate the distance covered before coming t...