Keisha writes that if an object has any external forces acting on it, then the object can be in dynamic equilibrium but not static equilibrium. Which statement best describes Keisha’s error? An object that is not moving is always in static equilibrium. An object that is moving must be in dynamic equilibrium. An object in either state of equilibrium must have no forces acting on it. An object in either state of equilibrium must have no net force acting on it.

the independent variable, or the one that is intentionally manipulated is the speed.

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