Question

State newtons second law of motion. express it mathematically and find SI unit of force from it.

Answer 1

✥ Answer :

› Newtons Second Law Of Motion ‹

According to Newton's second law of motion the rate of change of momentum of a body is directly proportional to the applied force ,and takes place in the direction in which the force acts.

Mathematically express :

$\boldsymbol{Force \propto \frac{change \: in \: mometum}{time \: taken} }$

$\boldsymbol{Force \propto \frac{mv - mu}{t} }$

$\boldsymbol{Force \propto m\frac{(v - u)}{t} }$

$\boldsymbol{Force \propto ma} \: \: \rm{ \{a = \frac{v - u}{t} \}}$

$\boldsymbol{Force = k \times m \times a}$

• putting k = 1

$\underline{ \boxed{\boldsymbol{Force = ma}}}$

• SI Unit of force

→ Force = mass × acceleration

→ F = m × a

→ unit of force = unit of mass × unit of acceleration

→ unit of force = kg × m/s²

→ unit of force = kgm/s²

• unit of force = Newton

→ unit of force = N

$\underline{\boxed{ \boldsymbol{1N = 1kgm/sec {}^{2} }}}$

Answer 2

Answer:

According to Newton' second law of motion, the rate of change of linear momentum of a body is directly proportional to the external force applied on the body, and this change takes place always in the direction of applied force.

Although the SI unit of total cross sections is m2, smaller units are usually used in practice.