Average velocity is defined as
now we have
when she cross the pool in time t1
when she cross the pool back to starting position
Here negative sign is for its return path direction which is reversed of its initial direction.
now for the round trip
displacement = 0
so v = 0
Answer: τ = 0
Explanation:
At constant angular velocity there is no angular acceleration therefore no torque.
τ = Iα
Answer:
Electric current
Explanation:
An electric current is the rate of flow of electric charge past a point or region. An electric current is said to exist when there is a net flow of electric charge through a region. In electric circuits this charge is often carried by electrons moving through a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in an ionized gas (plasma).
Answer:
k = 101.2 N / m
Explanation:
For this exercise we can use the relationship between work and energy
W = ΔK (1)
Where the work of the friction force is
W = fr x cos θ
As the friction force opposes the movement, the angle is 180º, so the kinetic product remains
W = - fr x
The friction force is given by the equation
fr = μ N
Let's use Newton's second law
Axis y
N - W = 0
N = W
We substitute
fr = μ mg
So the work is
W = - μ m g x
On the other hand, the variation in energy is
ΔEm = Em_final - Em_inicial
ΔEm = ½ k x² - ½ m v²
We substitute in our initial equation 1
-μ m g x = ½ k x² - ½ m v²
k = 2m / x² (- μ g x + ½ v²)
k = 2 2.00 / 0.190² (- 0.660 9.8 0.190 + ½ 2.07²)
k = 101.2 N / m
The decay function is of the form
where
N₀ = initial amount
k = decay constant
t = hours
The material decays by 10% in 95 hours. Therefore
The time for the half life is given by
Answer: The half life is 625 hours