A toy plane with a mass of 20 kg is flying at 10 m/s. What is its kinetic energy? A. 1 000 J
B. 200 J
C. 2 000 J
D. Cannot be determined

1000J

Explanation:

Given parameters:

Mass  = 20kg

Speed  = 10m/s

Unknown:

Kinetic energy  = ?

Solution:

To solve this problem, we use the kinetic energy equation:

  Kinetic energy  = m v²  

m is the mass

v is the speed

 Now insert the parameters and solve;

     K.E  =    x 20 x 10²   = 1000J

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.

the part of the wave he is travelling on is the crest