3. how difficult it is to change an object's motion
Answer:
Both rod have the same tensile stress
Explanation:
Given information,
The weight first rod,
= 1000 N
The length of first rod,
= 2.0 m
The weight second rod,
= 500 N
The length of second rod,
= 1.0 m
The equation of tensile stress, σ = 
where
σ = tensile stress (N/
or Pa)
F = Force (N)
A = Area (N/
or Pa)
so
σ1 =
, A = 2πl
= 
=
N/
now calculate σ2
σ2 = 
= 
=
N/
σ1/σ2 =
/ 
σ1/σ2 = 1
σ1 = σ2
Hence, the tensile stress of first and second rod are the same.
Mass-Energy is constant. If you are working then you are doing it spending energy. If you have a working rate so u also have a energy spending rate, which is called the power. As footballers working rate is too high(running, kicking, jumping, tackling, defensing etc)their energy spending rate i.e, required power is also high. Hence to be a footballer you need high power.
Your position at time
, relative to the stop line:

The Porsche's position:

a. You pass the Porsche immediately after the time it takes for
:

at which point you both will have traveled 7.8 m from the stop line.
b. The equation in part (a) has two solutions. The Porsche passes you at the second solution of about
, at which point you both will have traveled 29 m.
c. At time
, the Porsche is moving at velocity

so that at the moment it passes you, its speed is 13 m/s, which is about 46.8 km/h and below the speed limit, so neither of you will be pulled over.
Answer:
both charges will have different potential energies that will depend upon the charge magnitude.
Explanation:
It is given that both the charges are on the same equipotential line which means the potential V at which the two charges are is same.
Now the potential energy of a charge at potential V is given by
q×V where q is the charge value
Thus Higher the charge value for a given value of potential , higher will be the potential energy
Thus the larger charge will have higher potential energy and not the same.