Answer:
Step-by-step explanation:
1)
= 50 + (-9*8) *1
= 50 - 9.8
= 40.2 m/s
2) The acceleration of the ball at its maximum height equals to the force of gravity. -9.8 m/s²
3) The velocity at its top of the path:When the ball is thrown straight up, its velocity keeps on decreasing due the pull of gravity which pulls it towards the ground. So, the velocity at the top of its path is zero.
Answer:
The half-life of the radioactive substance is of 3.25 days.
Step-by-step explanation:
The amount of radioactive substance is proportional to the number of counts per minute:
This means that the amount is given by the following differential equation:
In which k is the decay rate.
The solution is:
In which Q(0) is the initial amount:
8000 counts per minute on a Geiger counter at a certain time
This means that
500 counts per minute 13 days later.
This means that . We use this to find k.
So
Determine the half-life of the radioactive substance.
This is t for which Q(t) = 0.5Q(0). So
The half-life of the radioactive substance is of 3.25 days.