Chapter 4 & 5 iGCSE PE revison

What is the main purpose of the cool-down phase after exercise?

• To build muscle mass

• To gradually return the body to its resting state

• To increase heart rate

• To burn more calories

Answer explanation

The main purpose of the cool-down phase is to gradually return the body to its resting state. This helps to stabilize heart rate and prevent dizziness, making it essential for recovery after exercise.

What immediate effect does exercise have on breathing rate?

• Decreases immediately

• Stays the same

• Increases to supply more oxygen

• Becomes irregular

Answer explanation

During exercise, the body's demand for oxygen increases, leading to an immediate rise in breathing rate. This increase helps supply more oxygen to the muscles, making 'Increases to supply more oxygen' the correct answer.

What happens to blood flow during exercise?

• Decreases to all parts of the body

• Remains constant

• Increases to working muscles

• Stops temporarily

Answer explanation

During exercise, blood flow increases to working muscles to supply them with more oxygen and nutrients, enhancing performance. This is crucial for sustaining activity and improving endurance.

What is the recovery period after intense exercise called?

• Oxygen deficit

• Energy surplus

• Oxygen debt

• Aerobic phase

Answer explanation

The recovery period after intense exercise is known as 'oxygen debt.' This term refers to the amount of oxygen required to restore the body to its pre-exercise state, highlighting the physiological processes that occur post-exercise.

Which force pair represents Newton's Third Law?

• Gravity and normal force
  

• Friction and tension

• Push and pull on different objects

• Action and reaction on the same object

Answer explanation

Newton's Third Law states that for every action, there is an equal and opposite reaction. The correct choice, 'Action and reaction on the same object', illustrates this principle, as it emphasizes the interaction between forces on a single object.

What type of lever is a pair of scissors?

• Third-class lever

• First-class lever

• Second-class lever

Answer explanation

A pair of scissors is a first-class lever because the fulcrum is located between the effort (where you apply force) and the load (the material being cut). This arrangement allows for efficient cutting action.

In a second-class lever, where is the load located?

• Between the effort and fulcrum

• At the end, after both effort and fulcrum

• Before both effort and fulcrum

• Equal distance from effort and fulcrum

Answer explanation

In a second-class lever, the load is positioned between the effort and the fulcrum. This arrangement allows the effort to lift a heavier load, making it an efficient lever type.

Which is a long-term effect of exercise on body composition?

• Increased body fat percentage

• Decreased muscle mass

• Decreased bone density

• Decreased body fat percentage

Answer explanation

Regular exercise leads to improved body composition, primarily by decreasing body fat percentage while increasing or maintaining muscle mass. This is a key long-term benefit of consistent physical activity.

Which long-term adaptation occurs in the respiratory system?

• Decreased vital capacity

• Reduced efficiency of gas exchange

• Increased number of alveoli

• Increased vital capacity

Answer explanation

Increased vital capacity is a long-term adaptation in the respiratory system, allowing for greater lung expansion and improved oxygen intake, which enhances overall respiratory efficiency.

What short-term effect occurs in muscles during intense exercise?

• Immediate muscle growth

• Lactic acid accumulation

• Decreased energy use

• Reduced blood flow

Answer explanation

During intense exercise, muscles produce energy anaerobically, leading to lactic acid accumulation. This buildup can cause fatigue and discomfort, making it the correct short-term effect.