Answer:
75 N upwards
Step-by-step explanation:
The weight of the groceries acting vertically downward.
It works as teh action force acting on the ground.
Now according to the Newton's third law, for every action there is an equal and opposite reaction.
So, the reaction on the cart is same in magnitude but opposite in direction.
Action = weight of the groceries = 75 N acting downward
Reaction = Action but the direction is opposite
Normal reaction = 75 N upwards