Answer:
it is very hard question for me sorry i cant solve it
Answer:
v = 18.84 m/s
Explanation:
Given that,
The length of the string, r = 1.5 m (it will act as radius)
The rubber stopper makes 120 complete circles every minute.
Since, 1 minute = 60 seconds
It means, its frequency is 2 circles every second.
Let we need to find the average speed of the rubber stopper. It can be calculated as follows :

d is distance,
and 1/T = f (frequency)

So, the average speed of the rubber stopper is 18.84 m/s.
The Answer is true, the saying opposites attract are true for magnets when poles match though they repel.
Answer:
A 1.0 min
Explanation:
The half-life of a radioisotope is defined as the time it takes for the mass of the isotope to halve compared to the initial value.
From the graph in the problem, we see that the initial mass of the isotope at time t=0 is

The half-life of the isotope is the time it takes for half the mass of the sample to decay, so it is the time t at which the mass will be halved:

We see that this occurs at t = 1.0 min, so the half-life of the isotope is exactly 1.0 min.