Solutions: Option B You can view the video tutorial here or the written solutions below.

A short-cut is to think about a couple who are in love or quarrel. When in love, both are walking together in one direction holding hand (i.e. current in both wires are in same direction ). Hence there is ATTRACTION between them. When the couple quarrel, both are walking in opposite direction (i.e. c urrent in opposite direction ). Hence there is REPULSION between them.

The distance-time (displacement-time) graph on the left is not related to the speed-time (velocity-time) graph. Both are of difference scenarios. But both shows the motion of 2 objects and both graph has an interception point. Do the interceptions point mean the same time in each graph? The image below shows the basic interpretation of the respective graphs. To have examples of the graphs with values and the step-by-step how to find the time it overtakes, refer to the videos below. Finding the exact time where the overtaking takes place.

01 The various physical quantities in kinematic Video tutorial 02: Acceleration Video tutorial 03: Graphical Analysis of Motion (Displacement (distance)-Time Graph and Velocity (speed)-Time Graph) Video tutorial 04: Describing the motion of the car – practice Video tutorial

Simply put, electric appliance can be very simple with just a live wire bring in the current and a neutral wire to bring the current out. The appliance can just work like this forever (without the hassle of having earth wire, fuse etc), provided there is no electric fault developed. Both the earth wire and the fuse are safety features to protect the user and the appliance respectively . Take a look at the video below to understand the rationale. Recall these notes given:

Answer: Option D

There are 3 scenarios with slight variations. Calculate the force F needed to pull the block up the inclined plane. View the video below to understand how to solve these types of question.

Though slinky coil is commonly used to demonstrate transverse and longitudinal waves, you must not quote it as an example for either of the waves. Transverse waves are waves in which the direction of the wave is perpendicular to the direction of the vibration of the particles. Examples are light wave, water wave or all the waves in the electromagnetic spectrum (which light is one of the waves. Longitudinal waves are waves in which the direction of the wave is parallel to the direction of the vibration of the particles.  Example is sound wave (inludes ultrasound and infrasound) Transverse Waves (slinky coil) Longitudinal Waves (slinky coil) Transverse Waves Animation Longitudinal Waves Animation