Answer:
The magnitude of force is 571.2 N.
Step-by-step explanation:
Given data :-
i) Mass of the box = 84 kg.
ii) Frictionless surface means friction force is zero.
iii)The force ( F ) which act on box = m*a.
iv) The time for which the box is in motion ( t ) = 5 seconds.
v) The distance traveled by box ( S ) = 85 meter.
Now to find magnitude of force we have to calculate the value of acceleration.
We know the equation of motion.
S = (u*t )+0.5 (a*t²)
85 = 0 + 0.5 * a *5² ( u = initial velocity = 0 )
a = 6.8 m²/s.
∴ F = m*a = 84 * 6.8 = 571.2 N