Sudhir walks 0.40 km in a direction 60.0° west of north, then goes 0.50 km due west. What is his displacement?

The displacement of Sudhir is 0.781 km.

Explanation:

Given;

initial distance, d₁ = 0.4 km = 400 m, N60.0°W

final distance, d₂ = 0.5 km

Make a sketch of Sudhir motion to form a right angled triangle;

(Check image uploaded).

Apply cosine rule to determine d "displacement"

d² = 500² + 400² - (2 x 500 x 400 x cos 120)

d² = 410,000 - (400,000 x -0.5)

d² = 410,000 - (-200,000)

d² = 410,000  + 200,000

d² = 610,000

d = √610000

d = 781.03 m

d = 0.781 km

Therefore, the displacement of Sudhir is 0.781 km.

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.