Một hòn đá có khối lượng 5kg bay với vận tốc 72kg/h . động lượng của hòn đá là

Momentum = 100 Kgm/s

Explanation:

Given the following data;

Speed = 72 km/h

Mass = 5 kg

To find the momentum of the stone;

First of all, we would have to convert the value of speed to meter per seconds.

Conversion:

72 km/h to m/s = (72 * 1000)/3600 = 20 m/s

Momentum can be defined as the multiplication (product) of the mass possessed by an object and its velocity. Momentum is considered to be a vector quantity because it has both magnitude and direction.

Mathematically, momentum is given by the formula;

Momentum = mass * velocity

Substituting the values into the formula, we have;

Momentum = 5 * 20

Momentum = 100 Kgm/s

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.