Which of the following is an example of an opposing force? A. Gravity pulling a ball down a hill
B. Wind blowing a leaf off of a tree
C. Gravity holding a rock still on the ground
D. Water pushing against someone as they wade through a pool

d

Explanation:

i dont really know

A. Gravity pulling a ball down a hill

Explanation:

Opposing force is a force that involves an interaction between two or more objects, and it causes a push or pull between the objects.

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s