2rocks of the same mass are rolling down a hill at different speeds (one faster than the other). which rick would have more kinetic energy? ?

Kinetic energy of an object depends on its mass and its speed.

If the masses are equal, then the rick with more speed has more kinetic energy.

The rock which is faster than the other have more kinetic energy.

Explanation:

Two rocks are of same mass are rolled down the hill at different speeds. Before the rocks are rolled, at rest they both will have same potential energy and zero kinetic energy. When the rocks are rolled, their potential energy reduces as they move forward and their kinetic energy increases from zero.

Since they are travelling at different speeds, one will be faster than the other, and so one rock reached faster than the other. The rock which reaches the ground first will have more kinetic energy than the other.

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