As we know that angular acceleration is given by

integrating both sides

again we can write

again integrating both sides

now put t = 3.91 s

**Answer:**

A plain mirrior is a mirrior with flat reflective surface.

hope it is helpful for you.

**Answer:**

72 joules

**Explanation:**

The potential energy of that hammer is a function of its displacement against gravity. Considering that it fell with a velocity of 12 m/s, it was its displacement against gravity that gave it this velocity. It will continue to move until its displacement to gravity is zero.

since the body is in motion; it has converted its potential energy (mgh, m is mass, g is acceleration due to gravity, and h is the height) to kinetic energy (energy due to motion, 1/2mv^2; m = mass, v = velocity or speed)

therefore the potential energy is equal to kinetic energy

mgh = 1/2mv^2 = 1/2 *1kg* 12*12 = 72 joules.

**A) Black**

If it absorbs all light it does not emit or reflect any, meaning the object will appear black

Protons and neutrons are composed of quarks

Answer:C ( quarks)