Assuming the cart rests on a perfectly smooth and horizontal surface, then we can apply Newton's second law,
F=ma => a=F/m
Acceleration, a = Force/mass = 16 N / 8 kg = 2 m/s^2
You need the kinematic equation for distance as a function of acceleration:
![d = [v(initial) *t] + 0.5a*t^{2}](https://tex.z-dn.net/?f=d%20%3D%20%5Bv%28initial%29%20%2At%5D%20%2B%200.5a%2At%5E%7B2%7D)
where a = gravitational acceleration 9.8m/s^{2}
v(initial) = starting velocity
t = time of fall
if the stone started at rest then v(initial) = 0 making the equation simply

Let me know if you still need further help :)
Answer:
<em>Well, I think the best answer will be is </em><em>B) Gravity. Good luck!</em>
Answer:
The force from the truck on the car is always equal to the force from the car on the truck.
Explanation:
According to Newton's third law; action and reaction are equal and opposite. Hence, when the big truck and small passenger car are involved in a collision, we expect that the force from the truck on the car is always equal to the force from the car on the truck. The forces on the car and the truck are equal in magnitude but opposite in direction.
This follows directly from Newton's third law of motion hence the answer above.