Object A has a mass of 20kg and object b has a mass of 80kg. After they are forced apart by a spring. Object A accelerates at a rate of 40 m.sec. What acceleration of object b> Show your math, and give the proper units.

Would I use the formula F=M
kg

so would this answer be 160 or 20

Please help:(

Think about whether a heavier object is easier or harder to accelerate - your answer should be obvious if you compare it to your real life experience.