As the reference height is at B, so above that reference height is considered positive, and below the reference height it is considered negative. Hence the height-time graph is as such. Consider a vertical oscillating object, similar to the simple pendulum, the middle is the fastest.

To get a sharp image on the screen, there are various methods and concepts that you have learned and can be applied here. View the video for the explanation:

There is a related question in Pure Physics 2021 P2 Q9, but slightly different. It asked about why home circuit of 230V is not suitable...

Flemeng's Left Hand Rule, using your left hand, with the thumb, 1st finger and 2nd finger all 90 degrees to one another. This is covered...

1) When a ball is thrown up and it comes down When the ball leaves the hand, there is no upward force acting on the ball. The only force...

Think of gradient as the steepness of a slope as you climb to the right (as time increases). 1) If it is getting steeper > increasing...

Scalar quantity is a quantity with magnitude but no direction. Vector quantity is a quantity with both magnitude and direction .

A common mistake is to state that the reason for switch to be on the live wire is “so that the switch can turn on/off the appliance”....