An advertisement claims that a particular automobile can "stop on a dime". what net force would actually be necessary to stop an automobile of mass 890 kg traveling initially at a speed of 48.0 km/h in a distance equal to the diameter of a dime, which is 1.8 cm ?

F = 4399 KN

Explanation:

given,

mass of automobile = 890 kg

initial speed = 48 km/h

                     = 48 × 0.278 = 13.34 m/s

using equation of motion

v² = u² + 2 a × s

0 = 13.34² - 2 a ×0.018

a = 4943.21 m/s²

F   = m × a

F   = 890 × 4943.21

F   =  4399456.9 N

F = 4399 KN

hence, the  Net force is F = 4399 KN

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.

the first american roller coaster was the mauch chunk switchback railway, built in the mountains of pennsylvania in the mid-1800s. the track, originally built to send coal to a railway, was reconfigured as a "scenic tour."