Physics chapter 1

Chapter 1.

Physical Quantity: a quantity that can be measured

Precision: the smallest unit an instrument can measure

Parallax error: When your eyes’ line of sight is not perpendicular to the ruler

Zero error: Introduced when using a metre rule with its zero end worn out.

Linearly: in a straight line

Scalar quantity: a physical quantity that has magnitude only

Vector quantity: a physical quantity that has both magnitude and direction

Volume of regular solids

Rectangular block = l×b×h

Cylinder = π r² h

Sphere = 4/3π(d/2)³

We can tell time by observing events that repeat at regular intervals/periods.

Each complete to-and-fro motion is one oscillation.

The period of a simple pendulum is the time taken for one complete oscillation. Pendulum clocks can be calibrated to measure time accurately by adjusting the length of the pendulum.

When we add scalars, we add their magnitudes only.

How to add vectors

When we add two or more vectors, we cannot add their magnitudes only. We need to find a single vector known as the resultant vector, which must be equivalent to the individual vectors combined in terms of magnitude and direction.

How to find resultant vector:

Vector A: Vector B:

V=R1SinΘ1 V=R2SinΘ2

H=R1CosΘ1   H=R2CosΘ2

 Rv = R1Sin(Θ)+R2Sin(Θ) 

 RH = R1Cos(Θ)+R2Cos(Θ) 

Resultant vector = √Rv^2 + RH^2

θ = tan−1(Rv/RH)