Question

A body has an acceleration of 20 km per sec2. Find the value in SI and cgs system

Answer 1

a= 20 km/s²
SI unit of acceleration, a is m/s²
and CGS unit is cm/s²

∴SI unit
1 km = 1000 m
∴20 km = 20000 m
SI unit = 20000 m/s²

CGS unit
1 km = 10⁵ cm
∴20 km = 2×10⁶ cm
CGS unit = 2×10⁶ cm/s²

Answer 2

In Si system ,
Units of physical quantities are the following
Length - Metres ( M )
Mass - Kilogram (Kg)
Time - Second (S)
Temperature - Kelvin (K)
Amount of substance - Mole (mol )
Current - Ampere (A)
Luminous intensity - Candela (Cd)

Here,
Acceleration is a derived quantity.
We can prove it by its equation
i.e ,
Acceleration = Velocity / time
but,
Velocity = Displacement / time
Which means,
Displacement is length.
So acceleration is derived from the fundamental quantities, length and time.

SI unit
----------

Unit of acceleration in SI system is m/s2
Acceleration is given as 20 Km/s2
Well considering in SI system it becomes

20 Km/s2 = (20 × 10^3 ) m/s2
= 20000 m/s2 //


Cgs system
---------------

In this system
Unit of length is Centimetres
&
Unit of time is seconds

Acceleration = 20 Km/s2

20 Km/s2 = 20 × 10^5 cm/s2
= 2000000 cm/s2 //