Answer
Acceleration of the sled $= 0.62$ $m/s^{2}$
Work Step by Step
We have,
$Force = Mass\times Acceleration$,
So,
$\frac{Force}{mass}= Acceleration$
Substituting the known values, it gives :
$\frac{5.2 N } {8.4 kg}=Acceleration$
$Acceleration = 0.619$ $m/s^{2} \approx 0.62m/s^{2} $
So, acceleration of sled is $0.62m/s^{2}$.
