Answer:
78.6 N
Step-by-step explanation:
Considering the change in kinetic energy is equal to force*time then knowing that kinetic energy change is given by
where m is the mass, v is velocity, subscripts f and i for final and initial respectively, f for force and t is time
![\triangle KE=0.5*1.5(7.7^(2)-8.9^(2))=0.19f\\F\approx 78.6N](https://img.qammunity.org/2021/formulas/physics/high-school/td7x5qnhq74b534fb61jxemq67uwceae8s.png)