Question

Which of the following quantities has ‘newton’ as its SI unit?
1. Force
2. Power
3. Energy
4. Torque

Answer 1

Correct Answer - Option 1 : Force

CONCEPT:

• Force: It is any interaction that, when unopposed, will change the motion of an object.
  • A force can cause an object with mass to change its velocity, i.e., to accelerate.
  • Force can also be described  as a push or a pull.
  • A force has both magnitude and direction, making it a vector quantity.
  • In SI base units: kg·m/s2 / Newton

Formula:

F = mass × acceleration = m × a

• Energy(E): It is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object.
  • Energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed. 
  • S.I unit of energy is Joules

Formula:

E = power × time

• Power(P): It is the amount of energy transferred or converted per unit of time.
  • In the International System of Units, the unit of power is the watt, equal to one joule per second.
  • In older works, power is sometimes called activity.
  • Power is a scalar quantity.

Formula:

P = energy/time

• Momentum(p): It is the product of the mass of a particle and its velocity. 
  • Momentum is a vector quantity; i.e., it has both magnitude and direction.
  • Isaac Newton's second law of motion states that the time rate of change of momentum is equal to the force acting on the particle.
  • SI unit: kilogram meter per second kg⋅m/s

Formula :

p = mass × velocity