Question 1

Which of the following best describes a free body diagram?

Accepted Answer

A diagram that shows all the forces acting on an isolated object, represented as vectors.

Question 2

What is the primary importance of having a frame of reference in physics problems?

Accepted Answer

It allows for consistent measurement and description of motion.

Question 3

Which of the following best describes the difference between a relative and a global frame of reference?

Accepted Answer

A relative frame of reference is based on a moving observer, while a global frame is fixed and external.

Question 4

Given two force vectors: $$\vec{F}_1 = 5\ \mathrm{N}$$ east and $$\vec{F}_2 = 12\ \mathrm{N}$$ north, what is the magnitude of the resultant vector?

Accepted Answer

$$13\ \mathrm{N}$$

Question 5

Which equation correctly defines torque ($$	au) $$produced by a force $$F$$ applied at a distance $$r$$ from the axis of rotation?

Accepted Answer

$$	au = r F \sin 	heta$$

Question 6

In the context of muscle force components, what is the difference between the Y (perpendicular) and X (parallel) components?

Accepted Answer

The Y component creates rotation (torque) about the joint, while the X component compresses or distracts the joint.

Question 7

Which of the following is an example of an internal force in the human body?

Accepted Answer

The force generated by the biceps muscle during elbow flexion.

Question 8

Which of the following is NOT a component of a lever in the human body?

Accepted Answer

The fulcrum is always the muscle insertion point.

Question 9

Which type of lever is most common in the human body?

Accepted Answer

Type III (third-class) lever

Question 10

Why are Type II levers at a mechanical advantage?

Accepted Answer

The effort arm is longer than the resistance arm, requiring less force to move a load.

Question 11

Why are Type III levers at a mechanical disadvantage?

Accepted Answer

The effort arm is shorter than the resistance arm, requiring more force to move a load.

Question 12

Which of the following is a real-life example of a first-class lever in the human body?

Accepted Answer

The neck joint when nodding the head.

Question 13

A person holds a 10 kg weight in their hand with their forearm horizontal. The distance from the elbow joint (fulcrum) to the hand is 0.35 m. What is the torque about the elbow due to the weight? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$34.3\ \mathrm{N \cdot m}$$

Question 14

Which of the following best explains why the human body has so many Type III levers?

Accepted Answer

They allow for greater speed and range of motion, despite requiring more force.

Question 15

If a muscle applies a force of $$50\ \mathrm{N} at an $$angle of $$60^\circ to a $$bone, what is the perpendicular (Y) component of the force?

Accepted Answer

$$43.3\ \mathrm{N}$$

Question 16

Which of the following statements about internal and external forces is correct?

Accepted Answer

Internal forces act within the body, such as muscle contractions, while external forces act on the body from the environment.

Question 17

A person pushes a box with a force of $$100\ \mathrm{N} at an $$angle of $$30^\circ$$ above the horizontal. What is the horizontal component of the force?

Accepted Answer

$$86.6\ \mathrm{N}$$

Question 18

Which of the following best describes the moment arm in a lever system?

Accepted Answer

The perpendicular distance from the axis of rotation to the line of action of the force.

Question 19

Which of the following is a correct statement about mechanical advantage in levers?

Accepted Answer

Mechanical advantage is the ratio of the effort arm to the resistance arm.

Question 20

A person stands on tiptoe, using the ball of the foot as the fulcrum. Which type of lever is this, and what is the mechanical advantage?

Accepted Answer

Type II lever; mechanical advantage greater than 1

Forces, Levers, and Biomechanics: Study Notes for Physics Students

Guida di studio - Domande di pratica

Study guide - Flashcard