PHY 101 Lecture Review: Physics in Biomedical Sciences

A set of comprehensive practice flashcards covering PHY 101 lectures on Units, Data Representation, Accuracy, Vectors, Forces, Newton's Laws, Friction, Connected Systems, and Levers.

How does the number of significant figures in a measured value relate to accuracy?

A larger number of significant figures indicates greater accuracy of the measurement.

What are the three main types of errors in measurement?

Random error, systematic error, and gross error.

How can random errors in measurements be minimized?

By taking a large number of observations and calculating their arithmetic mean.

How is the maximum error calculated for the expression $X = \frac{a^3 b^2}{c d^4}$?

$$\text{Error in } X = 3 \times (\text{error in } a) + 2 \times (\text{error in } b) + (\text{error in } c) + 4 \times (\text{error in } d)$$

To minimize total measurement error in a formula, which quantity must be measured most accurately?

The quantity with the maximum power in the formula, regardless of whether it is in the numerator or denominator.

What is the primary function of the electronic sweep circuit in a Cathode Ray Oscilloscope (CRO)?

It controls the voltage on the horizontal deflection plates to move the beam across the screen at a uniform rate and create a time base.

In a Cathode Ray Oscilloscope, what component determines how much the input signal is amplified vertically?

The vertical gain or vertical sensitivity control.

If an ECG sweep rate is set to $0.2\,\text{sec/cm}$ and a patient's heart rate is $60\,\text{beats per minute}$, what is the distance between consecutive ECG peaks on the screen?

$5\,\text{cm}$ (since $60\,\text{beats per minute}$ equals 1 beat per second).

Which brain wave band corresponds to frequencies of $8\text{--}12\,\text{Hz}$ on an EEG recording?

Alpha waves (medium waves).

What component of a Cathode Ray Tube produces the electron beam aimed at the fluorescent screen?

The electron gun (which includes the cathode and heater).

What distinguishes a vector quantity from a scalar quantity?

A scalar quantity is expressed by magnitude alone, whereas a vector quantity requires both magnitude and direction.

What is the process of resolution of a vector?

The process of splitting a single vector into two or more component vectors in different directions that together produce the same effect as the single vector alone.

What are the vertical and horizontal components of a vector with a magnitude of $60\,\text{N}$ acting at an angle of $40^\circ$ to the horizontal?

The vertical component $F_{\text{vert}}$ is $38.6\,\text{N}$ ($60\,\text{N} \times \sin(40^\circ)$) and the horizontal component $F_{\text{horiz}}$ is $45.9\,\text{N}$ ($60\,\text{N} \times \cos(40^\circ)$).

How is the magnitude of a 3D vector represented as $\mathbf{A} = x\mathbf{i} + y\mathbf{j} + z\mathbf{k}$ calculated?

$$\text{Magnitude of } \mathbf{A} = \sqrt{x^2 + y^2 + z^2}$$

What is the dot product of two vectors $\mathbf{A} = 3\mathbf{i} - 5\mathbf{j} + 6\mathbf{k}$ and $\mathbf{B} = -2\mathbf{i} + 3\mathbf{j} - 2\mathbf{k}$?

$-33$ (calculated as $3(-2) + (-5)(3) + 6(-2) = -6 - 15 - 12$).

Why are viral capsids/shells used as vectors in gene therapy?

They possess natural directionality to deliver working therapeutic genes into specific target cells.

What condition defines a balanced force acting on a body?

The net sum of all forces acting on the point or body is zero ($\sum F = 0$), keeping the object in equilibrium without causing motion.

How does Newton's First Law of Motion define inertia and its relation to mass?

Inertia is the tendency of a body to resist a change in its state of rest or uniform motion, and mass is a quantitative measure of inertia.

What is momentum, and how is it mathematically defined?

Momentum ($\mathbf{P}$) is the combined effect of mass and velocity, calculated as $\mathbf{P} = m\mathbf{v}$.

Why do equal and opposite action and reaction forces described in Newton's Third Law not cancel each other out?

Because the action and reaction forces act on two different bodies rather than on the same body.

How does a Ballistocardiograph (BCG) utilize Newton's Third Law to assess heart function?

When the heart pumps blood into the aorta each second, an equal and opposite reaction force is exerted on the body, which BCG sensors measure to evaluate heartbeat strength and blood volume pumped.

What is the Law of Conservation of Momentum for an isolated system of two colliding objects?

$m_1 u_1 + m_2 u_2 = m_1 v_1 + m_2 v_2$, where total momentum before collision equals total momentum after collision.

How does static friction compare to kinetic (dynamic) friction in magnitude?

Static friction is greater than kinetic friction ($\mu_s > \mu_k$).

How does the area of contact affect the coefficient of friction between two surfaces?

The coefficient of friction is independent of the area of contact between the surfaces.

What is the common acceleration $a$ of two connected masses $m_1$ and $m_2$ ($m_1 > m_2$) moving vertically over a pulley system?

$$a = \frac{(m_1 - m_2)g}{m_1 + m_2}$$

What is the formula for tension $T$ in the string connecting two masses $m_1$ and $m_2$ moving over a pulley?

$$T = \frac{2 m_1 m_2 g}{m_1 + m_2}$$

How is Mechanical Advantage (MA) defined for a lever system?

$$\text{MA} = \frac{\text{Output force}}{\text{Input force}} = \frac{\text{Input arm distance}}{\text{Output arm distance}}$$

What characterizes a Class Three lever system and what is an anatomical example of it?

In a Class Three lever, the Effort is located between the Fulcrum and the Load; an anatomical example is the elbow joint during a bicep curl.