Question 8 (4 points)

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A student wants to use a ramp to move boxes into a truck bed that is 3 m high. He has a choice of 2 different ramps. The length of one ramp is 4m, and the length of the other ramp is 6m.

Which one will make his work easier? (4 points)

Question 8 options:

4m, because he has to apply less force over a greater distance.

6m, because he has to apply more force over a greater distance.

6m, because he has to apply less force over a greater distance.

4m, because he has to apply more force over a greater distance.

Answer 1

To determine which ramp will make the student's work easier, we need to consider the concepts of force, distance, and the mechanical advantage provided by the ramps.

1. Ramp Height: Both ramps are used to raise boxes to a height of 3 m.

2. Ramp Length:

   • Ramp A: 4 m long
   • Ramp B: 6 m long

3. Mechanical Advantage: A longer ramp (6 m) allows for a gentler incline, which means that the force needed to move the boxes up the ramp is reduced. In general, a longer ramp allows you to apply less force over a longer distance.

Given this information, the option that describes the best choice is:

6m, because he has to apply less force over a greater distance.

This option aligns with the principle that longer ramps reduce the amount of force needed to lift the same height, making the task easier.

Answer 2

This question has two parts:

Make sure to answer both parts for full credit!

a) Using all the forms of energy that we've discussed this year, what would the conversion of energy look like from start to finish of a person running? (4 points)

b) What does the Law of Conservation of energy state? (4 points)

Answer 3

Sure! Here are the answers to both parts of your question:

a) Energy Conversions in a Person Running

When a person runs, various forms of energy are involved in the process. Here’s a breakdown of the energy conversions from start to finish:

1. Chemical Energy: The process begins with chemical energy stored in the food that the person has consumed. This energy is converted to usable energy through cellular respiration.

2. Mechanical Energy (Kinetic and Potential):

   • As the runner starts moving, the chemical energy is converted into mechanical energy. This mechanical energy has two components:
     • Kinetic Energy: Energy of motion as the runner's body and legs move forward.
     • Potential Energy: If the runner is moving up a slope, some of the mechanical energy is converted into gravitational potential energy as the height increases.

3. Thermal Energy: As the muscles work hard to run, some of the energy is lost as thermal energy due to friction in the muscles and the air resistance the body encounters. This is often felt as heat and results in sweat being produced to cool down.

4. Sound Energy: Running also produces sound energy—the noise of footsteps hitting the ground, breathing, etc.

So the sequence can be represented as:

Chemical Energy → Mechanical Energy (Kinetic and Potential) → Thermal Energy + Sound Energy

b) The Law of Conservation of Energy

The Law of Conservation of Energy states that energy cannot be created or destroyed; it can only be transformed from one form to another. This means that the total energy in a closed system remains constant over time. During energy transformations, while the forms of energy may change, the total amount of energy before and after the transformations remains the same.

In summary:

• Energy can change forms (e.g., chemical to kinetic to thermal), but the total energy in an isolated system is conserved.