Answer:
20 m/s
Explanation:
Recall that one of the equations of motions can be written:
v = u + at, (also see attached for reference)
Where,
v = final speed (we are asked to find this)
u = initial speed = 0 (because it starts from rest)
t = time taken = 5s
We simply substitute the given values into the equation:
v = u + at
v = 0 + (4)(5)
v = 20 m/s
Answer:
68 readings.
Explanation:
We need to take this problem as a statistic problem where the normal distribution table help us.
We can start considerating that X is the temperature of the solution, then
For a confidence level of 90% our 
is 1.645
Therefore,
Substituting for 
and re-arrange for n, we have that n is equal to
We need to make 68 readings for have a probability of 90% and our average is within 
Answer and Explanation
The concept of parallax and relative motion is responsible for this.
That is, the photographer's motion prompts her to see parallax for the man and the trees, because their positions appear to keep shifting even though they are not really moving.
Answer:
rise the air temperature is 0.179241 K
Explanation:
Given data
mass = 20000 kg
velocity = 18.5 m/s
long = 65 m
wide = 20 m
height = 12 m
density of the air = 1.20 kg/ m³
specific heat = 1020 J/(kg*K)
to find out
how much does the air temperature in the station rise
solution
we know here Energy lost by the train that is calculated by
loss in the kinetic energy that is = 1/2 m v²
loss in the kinetic energy = 0.5 × 20000 ×18.5²
loss in the kinetic energy is 3422500 J
and
this energy is used here to rise the air temperature that is KE / ( specific hat × mass )
so here
air volume = 65 ×20×12
air volume = 15600 m³
air mass = ρ × V = 1.2 × 15600
air mass = 18720 kg
so
rise the air temperature = 3422500 / ( 1020 × 18720)
rise the air temperature is 0.179241 K
