Old-fashioned pendulum clocks are powered by masses that need to be wound back to the top of the clock about once a week to counteract energy lost due to friction and to the chimes. one particular clock has three masses: 4.0 kg, 4.0 kg, and 6.0 kg. they can drop 1.3 meters. how much energy does the clock use in a week?

Energy, E = 178.36 J

Explanation:

It is given that,

Mass 1,

Mass 2,

Mass 3,

Height from which they are dropped, h = 1.3 m

Let m is the energy used by the clock in a week. The energy is equal to the gravitational potential energy. It is given by :

E = 178.36 J

So, the energy used by the clock in a week is 178.36 Joules. Hence, this is the required solution.

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

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