You need to know the height of a tower, but darkness obscures the ceiling. you note that a pendulum extending from the ceiling almost touches the floor and that its period is 28 s. the acceleration of gravity is 9.81 m/s 2 . how tall is the tower?

The height of the tower, where, the pendulum extending from the ceiling almost touches its floor is 195 meters.

Pendulum is the body which is pivoted a point and perform back and forth motion around that point by swinging due to the influence of gravity.

The time period of pendulum is time taken by it to complete one cycle of swing left to right and right to left.

It can be given as,

Here, (g) is the gravitational force of Earth and (L) is the length of the pendulum.

The period of the pendulum is 28 s and the acceleration of gravity is 9.81 m/s². Thus the length of the pendulum is,

As, the pendulum extending from the ceiling almost touches the floor. Thus, the height of the tower, is equal to the length of the pendulum.

Thus, the height of the tower, where, the pendulum extending from the ceiling almost touches its floor is 195 meters.

Learn more about the time period of pendulum here;

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the approx height of the tower must be 195 m

Explanation:

As we know that time period of simple pendulum is given as

now we know that

now we have

now rearrange the terms to find the value of L

so the approx height of the tower must be 195 m

a.

explanation:

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.