A75-m-long train begins uniform acceleration from rest. the front of the train has a speed of 18 m/s when it passes a railway worker who is standing 195m from where the front of the train started (see the figure below).a. what will be the speed of the last car as it passes the worker? b. express your answer to two significant figures and include the appropriate units.

The speed of the last car is 21.18 m/s.

Explanation:

Given that,

Length of train = 75 m

Speed of train= 18 m/s

Distance 195 m

Suppose the acceleration is constant.

We need to calculate the speed of the last car

Using equation of motion

For train and car,

Where, v = final velocity of train

u = initial velocity

s = distance

u'= speed of train

s'=distance

Put the value into the formula

Hence, The speed of the last car is 21.18 m/s.

a

explanation:

because they are cartillidge

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.