What is the average speed of a. an aircraft which travels 600 m in 10 seconds?
b. An athlete who runs 1000 m in 2 minutes?

sorry i dont know the answer sorry for that

Explanation:

Average Speed ( Velocity ) = [ Distance traveled ] ÷ [ time of the traveled distance in seconds ]

AS = 600 ÷ 10

AS = 60 m/s

2 minutes = 2 × 60 = 120 seconds

AS = 1000 ÷ 120

AS = 100 ÷ 12

AS = 25 ÷ 3

AS = 25/3 = 8.33 m/s ( approximately )

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.

1 the 4 is sig