Question

Calculate the net force acting on an object of mass and moving with a uniform velocity of $5kg,4m{{s}^{-1}}$respectively.

Answer 1

Hint: Net force acting on an object is equal to the product of the mass of the object and the acceleration of the object. Acceleration is the rate of change of velocity of the object. Uniform acceleration means that the velocity is constant throughout the entire distance traveled.
Formulas used:
$\begin{align}
  & F=ma \\
 & a=\dfrac{dv}{dt} \end{align}$

Complete step-by-step solution:
Given, the mass of the body, the velocity of the body as $m=5kg,v=4m{{s}^{-1}}$respectively. It is given that the object is traveling with uniform velocity. This means that the velocity doesn’t change with respect to time. So, $\dfrac{dv}{dt}=0$.
Now, if the rate of change of velocity is zero, the acceleration will eventually be zero.
$\begin{align}
  & a=\dfrac{dv}{dt}=0 \\
 & F=ma \\
 & F=(5)(0) \\
 & F=0N \\
\end{align}$
Therefore, therefore the net force on the object is zero.

Additional information:
An object is said to be traveling with a uniform velocity when the objects cover equal displacements in equal intervals of time. Change in velocity can cause motion in a body. They can even make changes in direction of an object eventually. Acceleration is the change in velocity. Uniform acceleration means that the object’s speed is increasing at a constant rate. If a car, for example, speeds up, slows down, and again speeds up as time is increasing, we can’t say the object is moving with uniform acceleration. Uniform motion is the motion in which the body covers equal distances in equal intervals of time. Here, non-uniform motion means that the body doesn’t cover equal distances in equal intervals of time.

Note: Uniform velocity of a body results in a net force of the body to zero. Uniform acceleration of a body doesn’t always need to be a net force acting on the body as zero. If the object has uniform acceleration, the net force on the body will be constant as mass, the other component is constant. This case is assumed without the presence of friction.