LEARN PHYSICS

  answer is A x and y are distances. R * y = P * x this is equilibrium condition  y decreases and therefore force at P should decrease. as P decreases, the force at Q should decrease to keep the rod equilibrium.  the answer is A  the child pulls the rope with a force of 12 and the tension in the rope pulls the child and sledge system.  making two equations for child and sledge system and child.  for child, 12 - Fr = ma  for child and sledge system, 24 = ma  24=  60 a , a = 0.4  12- Fr = 20 * 0.4 : fr= 4 N  you must be wondering from where do i get 24 N for the child and sledge system,  you need to understand the double pulley system where the efforts gets doubled by using two pulley to lift the load. the same concept is applied here to add 12 + 12 = 24N.

  the answer is B how  step 1 - underneath the graph mark 4 points at equal distances step2 - move the points as per the displacements of A, B ,C and D. you can see particle at B is at mean position, A to the right ,C to the left. D at mean position so B is the compression. the answer is D how  same method  step 1 - mark 4 dots at equal distances  step 2 - particle at B is at mean position , C to the left  A to the right , so B is high pressure  D is low pressure  the answer id B how  frequency is 0.5 hz  T = 2 s  so after 2nd quarter of the cycle , P will be at position B.,  In a  transverse, waves particles do not move from one place to another but move up and down about a mean position.