Common Measurements

Question 2

What are the SI units of measure?

Answer 2

kg, m, s, N, Joule, watt

SI units are the standard units of measurement used in scientific contexts.

Question 3

How is work calculated?

Answer 3

Work = Force x Distance

Work is measured in Joules (J) in SI units.

Question 4

What is the relationship between work, force, and distance in SI units?

Answer 4

Work (J) = Force (N) x Distance (m)

This equation illustrates how work is derived from force and distance.

Question 5

How do you convert kilograms to newtons?

Answer 5

1 Kg = 9.81 N

This conversion is essential for calculating force from mass in a gravitational field.

Question 6

How is biological energy quantified?

Answer 6

Energy in biological systems is measured in kilocalories

Kilocalories are often referred to simply as calories on food labels.

Question 7

What is one kilocalorie defined as?

Answer 7

The amount of heat energy needed to raise 1 Kg of water 1 degree C

This definition is fundamental in nutrition and metabolism studies.

Question 8

What is the conversion between kilocalories and kilojoules?

Answer 8

1 Kcal = 4.1868 kJ

This conversion is important for comparing energy values in different units.

Question 9

What is the formula for power?

Answer 9

Power = work/time

Power quantifies the rate of doing work.

Question 10

In SI units, how is power expressed?

Answer 10

Power (W) = work (J) / time (s)

1 Watt (W) is equal to 1 Joule per second.

Question 11

What is the equivalent of 1 Watt in terms of work and time?

Answer 11

1 W = 1 J/s

This relationship represents the definition of a watt.

Question 12

Calculate the force for an 80 kg mass.

Answer 12

Force = 80 kg x 9.81 N/kg = 784.8 N

This calculation uses the gravitational force to determine weight.

Question 13

What is the total distance covered if the distance per step is 0.35 m, with 20 steps per minute for 15 minutes?

Answer 13

Distance = 0.35 m/step x 20 steps/min x 15 min = 105 m

This calculation shows how to determine total distance from steps taken.

Question 14

What is the work done if the force is 784.8 N and the distance is 105 m?

Answer 14

Work = 784.8 N x 105 m = 82.404 kJ

This demonstrates how to calculate work from force and distance.

Question 15

What is the power output if the work done is 82404 J over 900 seconds?

Answer 15

Power = 82404 J / 900 s = 91.56 W

This calculation shows how to find power from work and time.

Question 16

What is direct calorimetry?

Answer 16

A method to measure body heat production to calculate energy expenditure

Example: mouse experiment with melting ice from body heat.

Question 17

What is indirect calorimetry?

Answer 17

Calculates energy expenditure from respiratory exchange ratio (RER) of CO2 and O2

This method is commonly used in metabolic studies.