Two students are watching a person riding a skateboard up and down a ramp. Each student shares what they think about the energy of the skateboarder as they ride up and down the ramp. Elisa: I think the skateboarder has the more total energy at the top of the ramp than the bottom of the ramp. Raymond: I think the skateboarder has the same total energy at all points on the ramp. Which student do you agree with? Why?

Elisa

Explanation:

I I agree with her because when you're at the top of the ramp you are going down and you are going to go down in an exact fast speed so you do have more energy and momentum at the top of the ramp

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.

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s