An athlete swings a ball, connected to the end of a chain, in a horizontal circle. the athlete is able to rotate the ball at the rate of 8.00 rev/s when the length of the chain is 0.600 m. when he increases the length to 0.900 m, he is able to rotate the ball only 6.00 rev/s. (a) which rate of rotation gives the greater speed for the ball?

6.0 rev/s gives greater speed for the ball.

Explanation:

given,

rotate a ball at the rate of = 8 rev/s

length of chain = 0.6 m

length increase to = 0.9 m

ball able to rotate  = 6 rev/s

(a) v = ω R                            

when R = 0.60                       ω = 8×2π            

v = 0.60 × 8 × 2π = 30.16 m/s                  

when R = 0.90                       ω = 6.00 × 2π    

v = 0.90 × 6.00 × 2π = 33.93 m/s                  

hence, 6.0 rev/s gives greater speed for the ball.

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.

beta is electron from nucleus

something from nucleus has changed, but charge must be same for cons of charge