A physicist is studying the properties of a pendulum to see if working in a bathyscaphe at the bottom of the Marianas Trench (10,916 meters below sea level!) changes its movement. The initial swing of the pendulum covers a distance of 50cm and each subsequent swing covers 90% of the distance of the previous swing. What is the total distance the pendulum has moved after 20 swings?

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

3. dark matter

empty space could also be a simple vacuum