Question 1

Time is a fundamental dimension and plays an important role in our daily life in describing events, processes, and many occurrences in our surroundings.

Accepted Answer

Time is indeed a fundamental dimension that helps us understand the sequence of events, duration, and occurrence of various phenomena in our daily life.

Question 2

A unit of measure commonly used to quantify air flow is cfm.What does cfm stand for?

Accepted Answer

CFM stands for Cubic Feet per Minute, which is a measure of how much air flows through a particular space in one minute. This unit of measurement is commonly used to measure the air flow rate of ventilation systems, air conditioning units, and other HVAC (heating, ventilation, and air conditioning) equipment. A higher CFM indicates a greater flow rate of air.

Question 3

Comparing speed and velocity,

Accepted Answer

Both statements A and B are partially correct, but statement B is more accurate. While speed is a scalar quantity that only measures how fast an object is moving, velocity is a vector quantity that measures both speed and direction. Therefore, statement B is more correct as it acknowledges both speed and direction as components of velocity. Statement C is incorrect as speed and velocity are not interchangeable terms, and statement D is incorrect as at least one of the statements is partially correct.

Question 4

A car starts from rest and 5 seconds later it is going  .What is the car's average acceleration?

Accepted Answer

We can use the formula for average acceleration (a) = (v_f - v_i) / t, where v_f is the final velocity, v_i is the initial velocity, and t is the time interval. In this case, v_f = 11 m/s, v_i = 0 m/s, and t = 5 s. Plugging in the values, we get a = (11 m/s - 0 m/s) / 5 s = 2.2 m/s^2. Therefore, the answer is B.

Question 5

A car traveling at constant speed as it rounds a curve is not experiencing angular acceleration.

Accepted Answer

Angular acceleration is the rate of change of angular velocity. Since the car is traveling at a constant speed, its angular velocity is not changing, and therefore there is no angular acceleration.

Question 6

If the pitcher's mound and home plate are  apart, how much time (in seconds) does the batter have to react to a  fastball?

Accepted Answer

Assuming the fastball travels at 90 miles per hour (typical of a Major League Baseball fastball), it would cover the distance from the pitcher's mound to home plate in approximately 0.45 seconds. Therefore, the batter would have approximately 0.45 seconds to react to the pitch.

Question 7

A thunderstorm is brewing in the distance.Upon seeing a flash of lightning you begin counting the seconds until you hear the thunder and notice that it took 5 seconds for the sound of thunder to reach you.Assuming the speed of sound in air to be  , estimate how far away was the lightning strike?

Accepted Answer

The answer of A thunderstorm is brewing in the distance.Upon...

Question 8

A car starting from rest has a constant acceleration of 5 m/s2.How long will it take to reach a speed of  ?

Accepted Answer

The answer of A car starting from rest has a...

Question 9

Because it takes the earth 24 hours to complete one revolution about its axis, every 15 degrees longitude corresponds to 1 hour.

Accepted Answer

This is true because there are 24 time zones around the world, each spanning roughly 15 degrees of longitude. Therefore, every 15 degrees longitude corresponds to one hour difference in time.

Question 10

When a solar flare occurs, how long does it take before a scientist sees it? (The Earth-Sun distance is  and the speed of light is approximately  .

Accepted Answer

The distance between the Earth and the Sun is about 93 million miles, which translates to about 8 light minutes. Therefore, it would take 8 minutes for a solar flare to be detected by a scientist on Earth. Choice D is the only option that matches this time frame. Options A (microseconds), B (milliseconds), and C (seconds) are much too short for the signal to travel such a great distance.

Question 11

Period and frequency mean the same thing.

Accepted Answer

Period and frequency are closely related, but they are not the same thing. Period refers to the time it takes for one complete cycle of a wave or oscillation, while frequency refers to the number of cycles per unit of time (usually measured in Hertz). They are inversely proportional: as frequency increases, period decreases and vice versa.

Question 12

Ten seconds after starting from rest, a motorcycle is moving at 20 m/s.What is the motorcycle's acceleration in m/s2? Assume constant acceleration.

Accepted Answer

The answer of Ten seconds after starting from rest, a...

Question 13

A jiffy is the amount of time it takes light to travel one centimeter.If the speed of light is approximately  , how many seconds are in a jiffy?

Accepted Answer

The answer of A jiffy is the amount of time...

Question 14

A slightly eccentric engineering professor rides a motorcycle whose front wheel has a diameter of  .While riding the motorcycle he notices that the front wheel is rotating at  .How fast is the motorcycle going?

Accepted Answer

The answer of A slightly eccentric engineering professor rides a...

Question 15

A useful variable of traffic information is density-how many cars occupy a stretch of a highway.

Accepted Answer

Density is a measure of the number of vehicles occupying a particular length of a roadway at any given time. It is a crucial traffic information variable used to calculate traffic flow, travel time, and congestion levels.

Question 16

A car travels along a certain road at an average speed of  and returns along the same road at an average speed of  .Calculate the average speed for the round trip.

Accepted Answer

The answer of A car travels along a certain road...

Question 17

A car starting from rest has a constant acceleration of 4 m/s2.How fast will it be going in 5 seconds?

Accepted Answer

The answer of A car starting from rest has a...

Question 18

Most engineering problems may be divided into two broad areas: steady and unsteady.

Accepted Answer

This statement is true. Steady problems involve conditions that do not change over time, while unsteady problems involve conditions that vary with time.

Question 19

If you pull a pendulum back and let it go, the time required for it to return to approximately the same place from which it was released is called

Accepted Answer

The time required for the pendulum to complete one full oscillation (i.e., to return to approximately the same place from which it was released) is called the period. The frequency refers to the number of oscillations the pendulum completes in a given amount of time, while the natural frequency is the frequency at which the pendulum oscillates when it is disturbed from its resting position. The amplitude refers to the distance that the pendulum swings from its resting position.

Question 20

The problem is said to be steady when the value of a physical quantity under investigation changes over time.

Accepted Answer

The problem is said to be unsteady when the value of a physical quantity under investigation changes over time. A steady problem is one in which the physical quantity of interest remains constant over time.

Quiz 8: Time and Time-Related Variables in Engineering

Time is a fundamental dimension and plays an important role in our daily life in describing events, processes, and many occurrences in our surroundings.

A unit of measure commonly used to quantify air flow is cfm.What does cfm stand for?

Comparing speed and velocity,

A car starts from rest and 5 seconds later it is going .What is the car's average acceleration?

A car traveling at constant speed as it rounds a curve is not experiencing angular acceleration.

If the pitcher's mound and home plate are apart, how much time (in seconds) does the batter have to react to a fastball?

A thunderstorm is brewing in the distance.Upon seeing a flash of lightning you begin counting the seconds until you hear the thunder and notice that it took 5 seconds for the sound of thunder to reach you.Assuming the speed of sound in air to be , estimate how far away was the lightning strike?

A car starting from rest has a constant acceleration of 5 m/s2.How long will it take to reach a speed of ?

Because it takes the earth 24 hours to complete one revolution about its axis, every 15 degrees longitude corresponds to 1 hour.

When a solar flare occurs, how long does it take before a scientist sees it? (The Earth-Sun distance is and the speed of light is approximately .