Newton's 2nd Law:The acceleration of an object is directly proportional to the net external force acting on the object and inversely proportional to the object’s mass.

Definition of acceleration:the rate of change of velocity. a_avg = (Delta v)/(Delta t)

Given:

vi = 0 } He started from rest

ti = 0 } ,, ,, ,, ,,

vf = 17 m/s

tf = 4 s

m = 190 kg

a = ?

F = ?

Solution:

To find the force, we need the mass and acceleration. We already got the mass, and now we're going to find the acceleration:

a_avg = (vf - vi)/(tf-ti) = (17-0)(4-0) = 4.25 m/s

Now, plug in:

F = ma = (190)(4.25) = 807.5 N