At a definite point, the bridge would begin oscillating to the matching rhythm as that
of the marching footsteps.
This oscillation would touch a determined peak when the bridge can
no longer tolerate its own
power and later collapses. So, soldiers are
systematic to break their steps
while passing a bridge.
Answer:
The current drawn by Horace’s reading glasses is 0.8 A.
Explanation:
Given that,
Resistance of each bulb, R = 2 ohms
Voltage of the system, V = 3.2 volts
These two bulbs are connected in series. The equivalent resistance will be 2 ohms +2 ohms = 4 ohms
Let I is the current drawn by Horace’s reading glasses. Using Ohm's law to find it such that :

So, the current drawn by Horace’s reading glasses is 0.8 A.
Answer:
The block has an acceleration of 
Explanation:
By means of Newton's second law it can be determine the acceleration of the block.
(1)
Where
represents the net force, m is the mass and a is the acceleration.
(2)
The forces present in x are
and
(the friction force):

Notice that
subtracts to
since it is at the opposite direction.

The forces present in y balance each other:

Therefore:
(3)
But
and writing (3) in terms of a it is get:

So the block has an acceleration of
.
Answer:
Isotopes are the elements having the same atomic number i.e same number of protons which in turn is equal to same number of electrons. Number of protons and electrons are equal as the atom is electrically neutral. So, the only option is A.
I hope it helps you !