Answer:
Only a backward force is acting, no forward force.
Explanation:
- Once released from the initial push, in absence of friction, the shopping cart would continue moving forward at a constant speed forever.
- As it would move at a constant speed, no net force would be acting on it.
- So, if it is gradually slowing, there must be a net force producing an acceleration in a direction opposite to the movement.
- This force is the kinetic friction force, and is the only force acting on the cart in the horizontal direction.
- As any friction force, opposes to the relative movement between the cart and the horizontal floor, which means that is directed backward.
- This is consistent with the direction of the acceleration of the cart.
Answer: 3.21 N


For weight, we will multiply by 

Hence, the rock would weigh 3.21 N.
It would be 12,000 because newton’s third 2nd law states F=ma (force=matter x acceleration) so 30x400 would be your force .
please mark brainliest and i hope this helps!
Newton's law of universal gravitation states that a particle attracts every other particle in the universe using a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers
Dispersion im pretty sure