Forces and Friction in Biomechanics

According to Newton's Third Law, if a person exerts a force on a wall, what happens?

• The wall exerts an equal and opposite force on the person.

• The wall exerts a greater force on the person.

• The wall exerts a lesser force on the person.

• The wall does not exert any force on the person.

What is the primary difference between static and dynamic friction?

• Static friction occurs when objects are moving, while dynamic friction occurs when objects are stationary.

• Static friction is always greater than dynamic friction.

• Dynamic friction is always greater than static friction.

• Static friction is independent of the surface area of contact.

Which of the following best describes ground reaction forces?

• The force exerted by the ground on a body in contact with it.

• The force exerted by a body on the ground.

• The force exerted by the air on a moving body.

• The force exerted by a body on another body.

How does friction impact athletic performance?

• It always decreases performance by slowing down movement.

• It can both enhance and hinder performance depending on the situation.

• It has no impact on performance.

• It only enhances performance by providing grip.

If a 10 kg object is at rest on a flat surface, what type of friction is acting on it?

• Dynamic friction

• Static friction

• Kinetic friction

• Rolling friction

Which of the following is an example of Newton's Third Law in action?

• A car accelerating on a highway.

• A swimmer pushing against the water to move forward.

• A ball rolling down a hill.

• A book resting on a table.

What unit is commonly used to measure ground reaction forces?

• Newtons

• Pounds

• Kilograms

• Metres per second

Which factor does NOT affect the magnitude of static friction?

• The nature of the surfaces in contact.

• The normal force.

• The speed of the object.

• The surface area of contact.

What happens to dynamic friction when the speed of an object increases?

• It decreases.

• It remains constant.

• It increases.

• It becomes zero.

In biomechanics, why is understanding ground reaction forces important?

• To improve the design of athletic footwear.

• To calculate the speed of a moving object.

• To determine the weight of an object.

• To measure the temperature of a surface.