How long must a simple pendulum be if it is to make exactly one swing per four seconds? (that is, one complete oscillation takes exactly 8.0 s.) express your answer to two significant figures and include the appropriate units.

Length of the pendulum will be 3.987 m

Explanation:

We have given time period of the pendulum T = 8 sec

Acceleration due to gravity

We have to find the length of the simple pendulum

We know that time period of the simple pendulum is given by

So length of the pendulum will be 3.987 m

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

e/c, where e is its total energy