Question

A force acting on a body of mass 10 kg is (2i+j+k),if the body is initially at rest.what will be the velocity at the end of 20 sec?

Answer 1

If You Need the Magnitude of Velocity, then

v=√(4² + 2² + 2²)
=√(24)
v=2√6 m/s

Answer 2

Given:

• Force = 2i + j + k
• Mass = 10 kg

To find:

• Velocity at t = 20 sec ?

Calculation:

First of all, let us calculate the net force:

$| f | = \sqrt{ {2}^{2} + {1}^{2} + {1}^{2} }$

$\implies | f | = \sqrt{ 4 + 1 + 1}$

$\implies | f | = \sqrt{ 6} \: N$

Now, the net acceleration will be :

$\implies \: a = \dfrac{ |f| }{m}$

$\implies \: a = \dfrac{ \sqrt{6} }{10} \: m {s}^{ - 2}$

Now, let's calculate the velocity after 20 sec:

$v = u + at$

$\implies \: v = 0 + \dfrac{ \sqrt{6} }{10} (20)$

$\implies \: v = 2 \sqrt{6} \: m {s}^{ - 1}$

So, velocity of the particle at the end of 20 seconds is 2√6 m/s .