Answer:
Average speed is 60 km/hour
Explanation:
When we need to calculate average speed, we use this equation:

Where:
position at the beginning
at the end


Then: 

Finally V = 60 km/hour
The linear velocity of a rotating object is the product of the angular velocity and the radius of the circular motion. Angular velocity is the rate of the change of angular displacement of a body that is in a circular motion. It is a vector quantity so it consists of a magnitude and direction. From the problem, the angular velocity is 5.9 rad per second and the radius is given as 12 centimeters. We calculate as follows:
Linear velocity = angular velocity (radius)
Linear velocity = 5.9 (12 ) = 70.8 cm / s
The linear velocity of the body in motion is 70.8 centimeters per second or 0.708 meters per second.
By Newton's 2nd law of motion, F = ma, where F is force, m is mass, and a is acceleration.
Rearranging this equation to find acceleration would give us:
a = F/m
The horizontal force to the right is 10N, because the box is pushed to the right with a force of 20N, and the friction force of 10N opposes that, so:
20N - 10N = 10N
The mass is 2kg.
Putting these values into the equation gives us:
a = F/m
= 10/2
= 5ms^-2
The acceleration of the box is 5ms^-2
A chemical compound consists of 2 or more chemical elements. They can be separated into simpler substances. Atoms of elements can be combined to form compounds. Molecules are groups of 2 or more atoms held together by chemical bonds. Minerals are chemical compound that can be found in nature. Valence is a measure of the combining power of an element.Answer: A. Atoms of elements.