(14 marks) two police officers on motorcycles leave the same police station at the
same time. motorcyclist #1 goes east at (3/5)c while motorcyclist #2 travels north at (4/5)c (these speeds are relative to the police station, of course). the driver of motorcycle #1 switches on his siren light 1 us (according to clocks in the police station
frame) after leaving the station. assume the lengths of the motorcycles are negligibly small (i. e., just consider the positions of the motorcyclists themselves).
(a) (5 marks) how long (according to clocks in the police station frame) after leaving
the station would the driver of motorcycle #2 "see the light from motorcycle #1
turn on (i. e., when the light from motorcycle #1 first arrives at motorcycle #2)?
(b) (5 marks) how long after leaving the station would the driver of motorcycle
#2 "see" this light turn on according to her watch? how far from the station
(according to motorcyclist #2) is motorcyclist #2 from the station at this instant?
(c) (4 marks) what is the velocity of motorcyle #1 according to the driver of motor-
cycle #2? answers:
a) duration is 1 us + 4.2 us = 5.2 us
b) duration is 3.12 us and distance is 0.75 km
c) velocity:
u' = -(4/5)
y=- (9/25)
can someone show me the method? !

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.

d is the correct answer

i don't understand. explain it clearly

this is an example of "committed" time.

committed time, as contracted time, takes need over essential and available time since it is seen as profitable work. it alludes to the time allotted to keep up a home and family. at the point when a man is commuting using committed time this individual may feel that the drive is an obligation to family, for example, strolling youngsters to class or driving a mate to work. contracted and committed time clients may feel that their commute could really compare to the commute of important or leisure time clients on the grounds that their commute is profitable work. in this manner, they might be more disposed to pick a mechanized method of movement.