Answer:
A <u>scientific model</u> is a physical and/or mathematical and/or conceptual representation of a system of ideas, events or processes. Scientists seek to identify and understand patterns in our world by drawing on their scientific knowledge to offer explanations that enable the patterns to be predicted.
Answer: <u>Option A: </u>The gas and food are examples of energy.
Explanation:
Work and energy are inter-related. Energy is required to do the work. An equal amount of energy is converted into work. Work and energy have same units. The SI unit is Joule.
The gas and food are sources of energy. They act as fuel. This energy is utilized to perform work. The gas is used to run the car. The food is metabolized inside the body which is a source of energy and utilized to perform every day work.
Hence, The gas and food are examples of energy.
Answer:
The air resistance on the skydiver is 68.6 N
Explanation:
When the skydiver is falling down, there are two forces acting on him:
- The force of gravity, of magnitude
, in the downward direction (where m is the mass of the skydiver and g is the acceleration due to gravity)
- The air resistance,
, in the upward direction
So the net force on the skydiver is:

where
m = 7.0 kg is the mass

According to Newton's second law of motion, the net force on a body is equal to the product between its mass and its acceleration (a):

In this problem, however, the skydiver is moving with constant velocity, so his acceleration is zero:

Therefore the net force is zero:

And so, we have:

And so we can find the magnitude of the air resistance, which is equal to the force of gravity:

Explanation:
we can use the formula F = ma
hence,
500 = 75a
a = 6.666 m/s² or 6(2/3) m/s²
hope this helps.