The velocity of a car teduces from 30 km/h as the car approaches a stop sigh. is this an example of positive or negative accelerationthe

The stopping car has negative acceleration.

Explanation:

 We know acceleration is the rate of change of velocity. That is

            Acceleration(a) = ( Final velocity - Initial velocity )/ Time taken.

            Here Final velocity = 0 km/h( car stops) and initial velocity = 30 km/h

             So acceleration = (0-30)/time = -30/ time

             Time is always positive , so -30/time is negative, so the stopping car has negative acceleration.

i sometimes feel that way too. i feel that i should hurt someone because they hurt me, but i wouldnt do it. that would make things so much worse i have so much experience with this stuff

explanation:

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.