Question

An object of mass M is at rest at the origin at time t = 0 . At that time, a force F = A(t^2) (where A is a positive constant and F is in newtons when t is in seconds) is applied to the object. After 2 s, the velocity of the object in m/s will be

Answer 1

Let's check

$\\ \rm\rightarrowtail F=ma$

$\\ \rm\rightarrowtail At^2=ma$

$\\ \rm\rightarrowtail 2^2A=ma$

$\\ \rm\rightarrowtail 4A=ma$

$\\ \rm\rightarrowtail a=4A/m$

$\\ \rm\rightarrowtail v=u+at$

• u is 0

$\\ \rm\rightarrowtail V=2a=8A/M$

Answer 2

Answer:

Explanation:

Let a be acceleration of mass M

By Newton 2nd Las, Force = mass * acceleration

F = A(t^2) = M * a

a = A(t^2) / M

By kinematics, final velocity = initial velocity + acceleration * time

Mass is at rest at t=0 so initial velocity

So velocity after 2s is

= 0 + A(2^2) / M * 2

= 8A/M