<< Chapter < Page Chapter >> Page >

Conceptual questions

A weather forecast states the temperature is predicted to be −5 ° C the following day. Is this temperature a vector or a scalar quantity? Explain.

scalar

Got questions? Get instant answers now!

Which of the following is a vector: a person’s height, the altitude on Mt. Everest, the velocity of a fly, the age of Earth, the boiling point of water, the cost of a book, Earth’s population, or the acceleration of gravity?

Got questions? Get instant answers now!

Give a specific example of a vector, stating its magnitude, units, and direction.

answers may vary

Got questions? Get instant answers now!

What do vectors and scalars have in common? How do they differ?

Got questions? Get instant answers now!

Suppose you add two vectors A and B . What relative direction between them produces the resultant with the greatest magnitude? What is the maximum magnitude? What relative direction between them produces the resultant with the smallest magnitude? What is the minimum magnitude?

parallel, sum of magnitudes, antiparallel, zero

Got questions? Get instant answers now!

Is it possible to add a scalar quantity to a vector quantity?

Got questions? Get instant answers now!

Is it possible for two vectors of different magnitudes to add to zero? Is it possible for three vectors of different magnitudes to add to zero? Explain.

no, yes

Got questions? Get instant answers now!

Does the odometer in an automobile indicate a scalar or a vector quantity?

Got questions? Get instant answers now!

When a 10,000-m runner competing on a 400-m track crosses the finish line, what is the runner’s net displacement? Can this displacement be zero? Explain.

zero, yes

Got questions? Get instant answers now!

A vector has zero magnitude. Is it necessary to specify its direction? Explain.

Got questions? Get instant answers now!

Can a magnitude of a vector be negative?

no

Got questions? Get instant answers now!

Can the magnitude of a particle’s displacement be greater that the distance traveled?

Got questions? Get instant answers now!

If two vectors are equal, what can you say about their components? What can you say about their magnitudes? What can you say about their directions?

equal, equal, the same

Got questions? Get instant answers now!

If three vectors sum up to zero, what geometric condition do they satisfy?

Got questions? Get instant answers now!

Problems

A scuba diver makes a slow descent into the depths of the ocean. His vertical position with respect to a boat on the surface changes several times. He makes the first stop 9.0 m from the boat but has a problem with equalizing the pressure, so he ascends 3.0 m and then continues descending for another 12.0 m to the second stop. From there, he ascends 4 m and then descends for 18.0 m, ascends again for 7 m and descends again for 24.0 m, where he makes a stop, waiting for his buddy. Assuming the positive direction up to the surface, express his net vertical displacement vector in terms of the unit vector. What is his distance to the boat?

h = −49 m u ^ , 49 m

Got questions? Get instant answers now!

In a tug-of-war game on one campus, 15 students pull on a rope at both ends in an effort to displace the central knot to one side or the other. Two students pull with force 196 N each to the right, four students pull with force 98 N each to the left, five students pull with force 62 N each to the left, three students pull with force 150 N each to the right, and one student pulls with force 250 N to the left. Assuming the positive direction to the right, express the net pull on the knot in terms of the unit vector. How big is the net pull on the knot? In what direction?

Got questions? Get instant answers now!

Suppose you walk 18.0 m straight west and then 25.0 m straight north. How far are you from your starting point and what is the compass direction of a line connecting your starting point to your final position? Use a graphical method.

30.8 m, 35.7 ° west of north

Got questions? Get instant answers now!

For the vectors given in the following figure, use a graphical method to find the following resultants: (a) A + B , (b) C + B , (c) D + F , (d) A B , (e) D F , (f) A + 2 F , (g); and (h) A 4 D + 2 F .

The x y coordinate system is shown, with positive x to the right and positive y up. Vector A has magnitude 10.0 and makes an angle of 30 degrees above the positive x direction. Vector B has magnitude 5.0 and makes an angle of 53 degrees above the positive x direction. Vector C has magnitude 12.0 and makes an angle of 60 degrees below the positive x direction. Vector D has magnitude 20.0 and makes an angle of 37 degrees above the negative x direction. Vector F has magnitude 20.0 and makes an angle of 30 degrees below the negative x direction.
Got questions? Get instant answers now!

A delivery man starts at the post office, drives 40 km north, then 20 km west, then 60 km northeast, and finally 50 km north to stop for lunch. Use a graphical method to find his net displacement vector.

134 km, 80 °

Got questions? Get instant answers now!

An adventurous dog strays from home, runs three blocks east, two blocks north, one block east, one block north, and two blocks west. Assuming that each block is about 100 m, how far from home and in what direction is the dog? Use a graphical method.

Got questions? Get instant answers now!

In an attempt to escape a desert island, a castaway builds a raft and sets out to sea. The wind shifts a great deal during the day and he is blown along the following directions: 2.50 km and 45.0 ° north of west, then 4.70 km and 60.0 ° south of east, then 1.30 km and 25.0 ° south of west, then 5.10 km straight east, then 1.70 km and 5.00 ° east of north, then 7.20 km and 55.0 ° south of west, and finally 2.80 km and 10.0 ° north of east. Use a graphical method to find the castaway’s final position relative to the island.

7.34 km, 63.5 ° south of east

Got questions? Get instant answers now!

A small plane flies 40.0 km in a direction 60 ° north of east and then flies 30.0 km in a direction 15 ° north of east. Use a graphical method to find the total distance the plane covers from the starting point and the direction of the path to the final position.

Got questions? Get instant answers now!

A trapper walks a 5.0-km straight-line distance from his cabin to the lake, as shown in the following figure. Use a graphical method (the parallelogram rule) to determine the trapper’s displacement directly to the east and displacement directly to the north that sum up to his resultant displacement vector. If the trapper walked only in directions east and north, zigzagging his way to the lake, how many kilometers would he have to walk to get to the lake?

North is up, east is to the right. A house and lake are shown. The x y coordiante system is also shown, with the origin near the house, the positive x direction to the right nad the positive y direction up. The vector from the house to the lake is shown as a straight red arrow, labeled as vector S, magnitude S=5.0 kilometers, and at an angle of 40 degrees above the posiitve x direction. Two meandering paths, path 1 and path 2, from the house to the lake are shown as dashed line.

3.8 km east, 3.2 km north, 7.0 km

Got questions? Get instant answers now!

A surveyor measures the distance across a river that flows straight north by the following method. Starting directly across from a tree on the opposite bank, the surveyor walks 100 m along the river to establish a baseline. She then sights across to the tree and reads that the angle from the baseline to the tree is 35 ° . How wide is the river?

Got questions? Get instant answers now!

A pedestrian walks 6.0 km east and then 13.0 km north. Use a graphical method to find the pedestrian’s resultant displacement and geographic direction.

14.3 km, 65 °

Got questions? Get instant answers now!

The magnitudes of two displacement vectors are A = 20 m and B = 6 m. What are the largest and the smallest values of the magnitude of the resultant R = A + B ?

Got questions? Get instant answers now!

Questions & Answers

Nature of the physical low
Rashika Reply
1/2 mv2 =mgh prove that
Rashika
study work energy theorem properly
Rohan
v2=u2+2gh...u=0...so 1/2 mv2=1/2m(2gh)=mgh
Talha
how can I become confident in physics
arshdeep Reply
practice more and more question ,,,,if u get trouble in any one question infact do that again and again.
jyotirmayee
is theory important or numericals
arshdeep
both ,,,,because without understanding theory ,,,,u can't able to solve problemsss or numericals
jyotirmayee
which books I can follow for IIT jee prep for mcq and which for mcq
arshdeep
what can make me good in physics
lovet
how can I solve qsns in physics cuz I understand most of the theories but facing problem during solving the qsns.
Rohan
Can someone please tell what really happened to planet Pluto
Ejiba Reply
what are the first 20 elements in periodic table.
Ejiba Reply
what happened to the rest now, or have you forgotten?
Ejiba
who discover periodic table?
lovet Reply
it wasn't discovered , it was made.and the person who made it was dmitri mendeleev. dobreinier and newland gave their laws before dmitri related periodic table but wasn't successful in their work
Ritik
Nope, numerous number of scientist had actually contributed in the making of periodic table. Dmitri Mendeleev succeeded making all the elements into the right order in accordance to their atomic number.
Dame
what is the Greek name for calcium
Oniyide Reply
Greek word for calcium is asvestio while Latin name is calf meaning lime or limestone
Ejiba
different types of wave
Yog Reply
longitudinal and transverse waves
Ravindra
a gun is kept in the state that it cannot move anywhere and the bullet is fired. Then what is the effect on the velocity of bullet and KE of gun ?
Gobinda Reply
want is meant by the term solar system
jafar Reply
it refers to the sun and all heavenly bodies revolving around it.
Danie
in addition to Danie's, a solar system is a collection of planets and their moons, asteroids, and other objects bound together by the Star's gravitational force directly or indirectly.
Galiwango
what is meant by total internal reflection
Akshay Reply
what iw meant by total internal reflection
Akshay
Lorentz force?
jyotirmayee
study fibre optics. .you will get total internal reflection
Siddhansh
wha
jyotirmayee
what is Lorentz force?
jyotirmayee
a ray of light traveling at an angle of incidence greater than critical angle from denser to rarer medium is totally reflected back into the denser medium is called total internal reflaction
Manoj
motion in strat line where is this chapter
Vijaybhai Reply
motion in straight line is kinematic's part
Ritik
yea
Manoj
motion in one dimension
Anil
what is Lorentz force?
jyotirmayee Reply
what is maxwell electromagnetic law?
jyotirmayee
at what angle should the two forces 2p and root 2p acts so that the resultant force is p root 10
Akshay Reply
what answer fir this
Akshay
what's the working difference between a dynamo and a pump?
Piyali Reply
a dynamo is basically a dc generator while pump is usually equipped with a motor
vedanth
a dynamo converts mechanical energy to electrical while a pump is opposite to that
vedanth
nice
Piyali
okay
Friday
why sea water looks bluish?
Piyali Reply
cuz the sky is blue...
Mehdi
you see the reflexion of the "blue" sky in the water
Mehdi
somewhere sea water turns green why?
Piyali
never seen bro... are u sure ?
Mehdi
ur answer was correct but due to the presence of phytoplankton color can be changed near the shore
Piyali
waaaww... you re awesome
Mehdi
because of the reflection of the sky
Friday
rays coming from the sun consist of all 7 colours ie.VIBGYOR. when the ray strikes surface of water,all colors gets absorbed by it except blue which gets reflected by it.so we find the sea water appearing bluish
Ritik
how can someone identify sea water from rain water
Oniyide
i think it's not possible as because rainwater consists of water from all kind of water bodies ie.lakes,seas etc but u can predict if u have a sea nearby ur home or city
Ritik

Get the best University physics vol... course in your pocket!





Source:  OpenStax, University physics volume 1. OpenStax CNX. Sep 19, 2016 Download for free at http://cnx.org/content/col12031/1.5
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'University physics volume 1' conversation and receive update notifications?

Ask