If applicable, the method of instantaneous center can be used to determine the of any point on a rigid body.

velocity and acceleration

Explanation:

The method of instantaneous center of rotation in plane motion is used in determining an imaginary point D, with respect to which all the particles of the rigid object rotate at the same angular velocity ω. Using this concept can be determined the absolute velocity of any point of the rigid body.

As the body undergoes planner motion, the fixed point on the body does not move at an instant. All the velocity vectors of all the other points perform a rotation.

The velocity of the points on the rigid body can be calculated, but the acceleration is fixed. The only acceleration it possesses is the centrifugal acceleration. The tangential acceleration is zero.

Therefore, the method of instantaneous center can be used to determine the velocity and acceleration of any point on a rigid body.

Velocity and Acceleration

Explanation:

- Instantaneous center (IC) of rotation in plane motion of a rigid body or a composite body is used to determine an imaginary point A in planar space R2. All the composing bodie(s) undergo rotation with constant angular speed (w) which is at a distance (r) from the IC. The absolute velocity of any point of the rigid body is given by:

                                    v = r*w

- As the body undergoes planner motion, the IC is fixed whether located on the body or not . All the velocity vectors of all the other points perform a rotation.

- The tangential acceleration reduce to zero and only centripetal acceleration exists.

- Hence, the method of IC can be used to determine absolute velocity (v) and centripetal acceleration (ac).

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.