The force needed to accelerate a stationary 2000 racing car to a speed of 144 km/h in a distance of 80 meters

518400 Newton

Explanation:

Force F = mass m * Acceleration a

a = velocity v / time t

v = distance d / t

Therefore;

F = m * v² / d

with m = 2000 (unit not defined but say g)

v = 144 Km/h

d = 80 meters =0.08Km

F = 2Kg * 144Km/h * 144Km/h / 0.08Km

F = 518400 Newton

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.

when it gains or loses electrons