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:
<em>Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses.[1] All stars are formed from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-seque</em>
Answer:

Explanation:
M = Mass of Earth
G = Gravitational constant
R = Radius of Earth
The acceleration due to gravity on Earth is

On new planet

Dividing the two equations we get

The acceleration due to gravity on the other planet is 
Answer:

Explanation:
Using the first law of thermodynamics:

Where
is the change in the internal energy of the system, in this case
,
is the heat tranferred, and
is the work,
with a negative sign since the work is done by the system.
From the previous equation we solve for heat, because it is the unknown variable in this problem

And replacing the known values:



The negative sign shows us that the heat is tranferred from the system into the surroundings.
Answer:
Part a)

Part b)
Ball thrown downwards =
Ball thrown upwards =
Part c)

Explanation:
Part a)
Since both the balls are projected with same speed in opposite directions
So here the time difference is the time for which the ball projected upward will move up and come back at the same point of projection
Afterwards the motion will be same as the first ball which is projected downwards
so here the time difference is given as



Part b)
Since the displacement in y direction for two balls is same as well as the the initial speed is also same so final speed is also same for both the balls
so it is given as




Part c)
Relative speed of two balls is given as


now the distance between two balls in 0.8 s is given as


