Answer:
F=m x a
(F is force ,M is mass and A is acceleration)
in thisncase the Mass is given but we need to find ou the acceleration
Formula for acceleration-
a=(v - u)/t
(v is final velocity , u is initiatal velocity and t is time)
a = (0 - 80)/4
a= -80/4
a= -20
By substituting the values-
F= m x a
F= 1500 x -20
F=-30000N
Thus the force acted is -30000N
hope this helps
