Answer:
The correct answer is a
Explanation:
The speed of a sound wave depends on the square root of the modulus of compressibility and the density of the medium.
For the same medium, the speed of sound depends on the temperature of the fora
v =
Therefore, the different results that are obtained are due to changes in temperature. The correct answer is a
since this way it has the values of the speed of sound for each temperature, for which it can compare with the results obtained from the trip.
Answer:
The one with highest velocity
Explanation:
The momentum of an object is given by
where
m is the mass of the car
v is the velocity of the car
In this problem, we have two identical cars: identical means they have same mass, so
The momentum of car 1 is
while the momentum of car 2 is
By comparing the two expressions, we see that the car with greatest momentum is the one with highest velocity, since the mass is the same.
Answer:
v = 9.04 m / s
Explanation:
For this exercise we can use the relation that the work of the non-conservative force (friction) is equal to the variation of the mechanical energy of the system.
W = Em_f - Em₀ (1)
Starting point. Lower slope
Em₀ = K = ½ m v²
highest point. Where is the skier at a height h
Em_f = U = m g h
The work of rubbing
W = -fr x
the negative sign is because the friction force opposes the movement.
Let's set a reference system where the x axis is parallel to the slope and the y axis is perpendicular
let's use trigonometry to break down the weight
cos θ = W_y / W
sin θ = Wₓ / W
W_y = W cos θ
Wₓ = W sin θ
Y axis
N - Wₓ = 0
N = mg sin θ
X axis
fr = m a
the friction force has the expression
fr = μ N
fr = μ mg sin θ
we look for the job
W = - μ mg sin θ x
where x is the distance along the slope
we substitute in 1
-μ mg sin θ x = mg h - ½ m v²
let's use trigonometry to find the distance x
tan 30 = h / x
x = h / tan 30
we substitute
- = m gh - ½ m v²
we use
tan 30 = sin30 / cos30
v² = 2g h + 2 μ g h cos 30
v =
let's calculate
v =
v = 9.04 m / s
Answer: 1) t=0.5 s; S=6.225 m and v=14.9 m/s
2) t=1 s; S=14.9 m and v=19.8 m/s
3) t=1.5 s; S=26.05 m and v=24.7 m/s
Explanation:
The displacement is given by
and final velocity is given by
where is the initial velocity
is acceleration
is time taken
Case 1: when time is 0.5 s
The displacement is
the velocity is
Case 2: when t=1 sec
The displacement is
the velocity is
Case 3: t=1.5 s
The displacement is
the velocity is