Aroller coaster has a mass of 275 kg. it sits at the top of a hill with height 85 m. if it drops from this hill, how fast is it going when it reaches the bottom? (assume there is no air resistance or friction.)

Explanation:

Given that,

Mass of the roller costar, m = 275 kg

It sits at the top of a hill with height 85 m, h = 85 m

We need to find the speed with which it is going when it reaches the bottom. It can be calculated using the conservation of energy as :

g is the acceleration due to gravity

v = 40.81 m/s

So, the speed of the roller coaster when it reaches the bottom is 40.81 m/s. Hence, this is the required solution.

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.