Physics Class: Measurement and Errors

Questions and Answers

What is the vertical velocity of a projectile at its highest point?

It is at its maximum value.

It is zero. (correct)

It increases due to gravity.

It is negative.

Which statement accurately describes the horizontal velocity of a projectile?

It decreases due to air resistance.

It is affected by gravity.

It varies with the launch angle.

It remains constant in the absence of air resistance. (correct)

What shape does the trajectory of a horizontally thrown object follow?

A circular path.

A straight line upwards.

A horizontal line.

A parabolic curve. (correct)

In projectile motion, what is the effect of launching at a 60° angle compared to a 30° angle?

It results in greater maximum height. Signup and view all the answers

What is centripetal force and its role in circular motion?

It points towards the center of the circular path. Signup and view all the answers

What is the primary difference between accuracy and precision in measurements?

Accuracy indicates the closeness to the true value, while precision indicates consistency of measurements. Signup and view all the answers

Which of the following best describes systematic errors?

Flaws in instruments that cause consistent errors. Signup and view all the answers

How would you add two vectors that are pointing in the same direction?

Add their magnitudes directly to get the resultant vector. Signup and view all the answers

What happens when two vectors of equal magnitude but opposite direction are added together?

The resultant vector cancels out to zero. Signup and view all the answers

What is the acceleration experienced by an object in free fall near Earth's surface?

Constant acceleration of 9.8 m/s downwards. Signup and view all the answers

When interpreting a velocity-time graph, what does a straight line with a negative slope indicate?

The object is decelerating or slowing down. Signup and view all the answers

Which formula is used to calculate acceleration?

a = Δv/Δt Signup and view all the answers

What characterizes projectile motion?

The motion occurs in two dimensions under the influence of gravity. Signup and view all the answers

Study Notes

Scientific Notation

Used to express very large or very small numbers efficiently.
Example: 5.367×10⁻³⁵ demonstrates the correct format.

Accuracy vs Precision

Accuracy measures closeness to the true value, akin to hitting the goal.
Precision indicates the consistency of repeated measurements; can be high even if inaccurate.
Accurate measurements guarantee closeness to the true value but aren't always precise.

Systematic Errors

Consistent errors arise from instrumental or procedural flaws.
Example: An uncalibrated balance can introduce systematic errors.

Random vs Systematic Errors

Random Errors: Unpredictable and affect the precision of measurements.
Systematic Errors: Consistent and affect the accuracy of measurements.

Adding Vectors

Vectors have both magnitude and direction and require specific methods for addition.
When vectors point in the same direction, their magnitudes add directly.

Vector Addition Methods

Graphical Method: Add vectors by positioning them head-to-tail; measure the resultant.
Algebraic Method: Use magnitudes and trigonometry (sine, cosine, tangent) for direction.

Adding Opposite Vectors

Two equal magnitude vectors in opposite directions result in a total magnitude of zero.

Resultant Vector Calculation

Adding perpendicular vectors necessitates using the Pythagorean theorem for magnitude and trigonometry for direction.

Constant Velocity

An object moving at a constant velocity has zero acceleration.

Free Fall Acceleration

Objects in free fall near Earth’s surface accelerate downwards at 9.8 m/s².

Calculating Acceleration

Formula: a = Δv/Δt.
Example: Changing velocity from 0 to 20 m/s in 5 seconds results in an acceleration of 4 m/s².

Negative Slope on Velocity-Time Graph

Indicates that an object is slowing down.

Velocity-Time Graph Interpretation

A straight line with a negative slope signifies deceleration.

Accelerating vs Constant Speed

A car accelerating (Car A) will eventually surpass a car moving at a constant speed (Car B).

Projectile Motion

Motion of an object in two dimensions under gravitational influence follows a parabolic path.

Vertical Velocity in Projectile Motion

At the apex of its trajectory, the vertical velocity is zero and changes solely due to gravity.

Projectile Motion Components

Constant horizontal velocity when unaffected by air resistance.
Vertical velocity alters due to gravitational acceleration.

Range in Projectile Motion

Defined as the total horizontal distance traveled by the projectile.

Constant Horizontal Velocity in Projectile Motion

Gravity affects only vertical motion, ensuring horizontal velocity remains unchanged.

Trajectory of a Horizontally Thrown Object

Follows a parabolic curve due to gravity acting downwards.

Projectile Motion Calculations

Kinematic equations and trigonometry can be utilized to determine time of flight and maximum height.

Projectile Launch Angle

A launch angle of 30° achieves greater horizontal distance, while 60° maximizes height.

Horizontal vs Dropped Ball

Both balls reach the ground simultaneously in the absence of air resistance.

Forces in Circular Motion

Centripetal Force acts towards the center, keeping objects in circular paths.
Centrifugal Force is a perceived force resulting from inertia, acting outward in rotation.

Circular Motion

Objects in circular motion continuously change direction due to the centripetal force directed towards the center.

Inspirational Quote

“Don’t watch the clock. Do what it keeps. Keep going.”