Answer:
4. Becomes softer as temperature rises
Explanation:
An amorphous solid is any noncrystalline solid in which the atoms and molecules are not organized in a definite lattice pattern. Such solids include glass, plastic, and gel. Solids and liquids are both forms of condensed matter; both are composed of atoms in close proximity to each other.
Answer:
The time interval is 
Explanation:
From the question we are told that
The angular acceleration is 
The time taken is 
The angular displacement is 
The angular displacement can be represented by the second equation of motion as shown below

where
is the initial velocity at the start of the 4 second interval
So substituting values

=> 
Now considering this motion starting from the start point (that is rest ) we have

Where
is the angular velocity at rest which is zero and
is the angular velocity after 4.0 second which is calculated as 12 rad/s s

=> 
Answer:
2.35 m/s²
Explanation:
Given that
Mass of the smaller crate, m₁ = 21 kg
Mass of the larger crate, m₂ = 90 kg
Tensión of the rope, T = 261 N
We know that the sum of all forces for the two objects with a force of friction F and a tension T are:
(i) m₁a₁ = F
(ii) m₂a₂ = T - F, where m and a are the masses and accelerations respectively.
1) no sliding can also mean that:
a₁ = a₂ = a
This makes us merge the two equations written above together as:
m₂a = T - m₁a
If we then solve for a, we would have something like this
a = T / (m₁+m₂)
a = 261 / (21 + 90)
a = 261 / 111
a = 2.35 m/s²
Therefore, the needed acceleration of the small crate is 2.35 m/s²