Answer:
To calculate the percentage of l-131 that has decayed up to the year 2021, we need to determine how many half-lives have passed from 1959 to 2021 and then calculate the remaining percentage.
The half-life of l-131 is 8.02 days.
First, calculate the number of half-lives that have passed from 1959 to 2021:
Number of years = 2021 - 1959 = 62 years
Since each year has approximately 365 days:
Number of days = 62 years * 365 days/year = 22,630 days
Now, calculate the number of half-lives:
Number of half-lives = Number of days / Half-life = 22,630 days / 8.02 days/half-life ≈ 2822 half-lives
Now, we know that each half-life reduces the remaining amount to half. So, to calculate the percentage remaining after 2822 half-lives:
Percentage remaining = (1/2)^2822 * 100 ≈ 0%
So, approximately 0% of the initial l-131 has decayed up to the year 2021.
The mass of water in the kettle is 0.50 kg.
The specific heat capacity of water is 4200 J/kg °C.
The initial temperature of the water is 100 °C.
Calculate the average power output from the water in the kettle to the surroundings in 2 hours
300 J
400 J
1000 J
Answer:
The K.E of the pendulum is, K.E = 200 J
Explanation:
Given data,
The kinetic energy of the bob of the pendulum at the bottom, K.E = 600 J
The potential energy at the height 4 m, P.E = 400 J
According to the conservation of energy, the total energy of the mechanical system should be conserved.
At the bottom of the swing, the entire mechanical energy of the pendulum is purely kinetic. Therefore the total energy
E = P.E + K.E
= 0 + 600 J
= 600 J
Therefore, the total energy of the system, E = 600 J
At height 4 m, the total energy of the system remains the same.
Therefore,
600 J = 400 J + K.E
K. E = 600 J - 400 J
= 200 J
Hence, the K.E of the pendulum is, K.E = 200 J
The shorter the time required to cover the same distance, the greater the speed of the RC car.
Acceleration is rate of change of velocity.
a = acceleration (m / s²)v = final velocity (m / s)
u = initial velocity (m / s)
t = time taken (s)
d = distance (m)
Let us now tackle the problem!
The formula for finding speed is:
v = velocity (m/s)
s = distance (m)
t = time taken (s)
From the formula above, it is clear that speed is inversely proportional to travel time. The shorter the time required to cover the same distance, the greater the speed of the RC car.
For example, let's look at the data in the table in the attachment. RC Car B has the greatest speed
Grade: High School
Subject: Physics
Chapter: Kinematics
Keywords: Velocity , Driver , Car , Deceleration , Acceleration , Obstacle , Speed , Time , Rate
The expiration date on a product refers to the last date a product should be used
or should be costumed by
I hope that's help !