Question1 : A stone of mass 0.5 kg is accelerating at 10 m·s−2 towards the earth.

What is the force exerted by the earth on the stone?
What is the force exerted by the stone on the earth?
What is the acceleration of the earth, given that it’s mass is 5.97 × 1027 kg?

Question 2: A truck of mass m1 = 1000 kg pulls a trailer with a mass m2 = 3000 kg. The frictional force on the truck is 1000 N and on the trailer is 2000 N. The truck engine exerts a force of 8000 N.

Calculate the acceleration of the truck and trailer, and the resultant force on the truck.