Physics Chapter 3

A bicycle courier accepts a package and bikes 3 blocks east to the intersection of the street shown on the address label. Encountering road construction, the courier detours by continuing one block east, one block north, and one block west. The courier then bikes two blocks north to the address. What is the resultant displacement of the courier? Use the graphical method.

(Refer to image for #10 on Section Quiz: Introduction to Vectors)

In a school playground, a child runs 5 m in the x-direction and then 2.0 m in the -y-direction. Which expression represents the magnitude of the child's resultant displacement?

(square root) (5m)^2+ (2m)^2

A skier slides onto a horizontal patch of slushy snow at velocity Vskier, and slows to a constant speed without changing direction. Which of the following expressions could be the skier's resulting velocity?

+1/4 Vskier

A car traveling at the legal speed limit has velocity +Vcar with respect to the road. You are in another car traveling in the opposite direction at the legal speed limit with respect ot the road. As the first car approaches you, what is the velocity relative to you?

+2Vcar

If the float has a velocity of +Vfloat with respect to the ground, what is the velocity of the clown as observed by the child?

+Vfloat

The velocity of a passenger relative to a boat is -Vpb. The velocity of the boat relative to the river it is moving on is +Vbr. The velocity of the river to the shore is +Vrs. What is the velocity of the passenger relative to the shore? Assume the + direction is east for all observers.

-Vpb + Vbr + Vrs

A duck maintains a constant swimming speed of 0.50 m/s relative to the water. As it swims across a creek that has a constant downstream current of 0.30 m/s, a naturalist sitting on the bank observes its motion. What is the duck's speed as observed by the naturalist?

.58 m/s

Another student chose east as the direction of the +x-axis. At what orientation with respect to the +x-axis should this student draw the vector representing the velocity of the second plane?

15.0 degrees counterclockwise from the +x-axis

In a movie production, a stunt person must leap from a balcony of one building to a balcony 3.0 m lower on another building. If the buildings are 2.0 m apart, what is the minimum horizontal velocity the stunt person must have accomplish the jump? Assume no air resistance and that Ay= -g=-9.81 m/s^2

2. 6 m/s

In a diagram, a student draws a vector representing the velocity of a plane traveling at 525 km/h 18.0 degrees east of north as a vector lying along the +x-axis. To represent the velocity of another plane traveling at 478 km/h 75.0 degrees east of north on the diagram, at which orientation with respect to the +x-axis should the student draw this vector?

57.0 degrees clockwise from the +x-axis

A vector that has components that lie along the -x axis and the +y axis is oriented at angle A measured counterclockwise from the +x axis. Which of the following ranges gives the values of angle A?

90 degrees < A < 180 degrees

In a blinding blizzard, a reindeer trudges 310 m 45 degrees east of south across the tundra. How far south does the reindeer move?

About 219.2 m

A volleyball player taps a volleyball well above the net. The ball's speed is least...

At the highest point of its path

What quantity is used to describe motion as an example of a vector quantity?

Average velocity

If the x-component of B equals the magnitude of B, then...

By equals zero

Which of the following is a frame of reference for measuring motion?

Coordinate system

Which of the following represents the vector resulting in the subtraction of the displacement vectors d2-d1 shown in the figure?

D.

If vectors are moved according to the rules of the triangle method of vector addition, then the resultant vector is drawn...

From the tail of the first vector to the tip of the last vector

For an object to be a projectile, it must be in free fall and its initial velocity must

Have a horizontal component

A baby drops a ball from her hand resting on the serving tray of her high chair. Simultaneously, she knocks another ball from the same tray. Which statements are true? I. Both balls strike the ground at the same time. II. The dropped ball reaches the ground first. III. The knocked ball reaches the ground first. IV. Both balls strike the ground at the same speed.

I and IV

The dumbbell's motion as described by an acrobat walking in the parade is very similar to the clown's description of the dumbbell's motion. What do you know about the motion of the acrobat?

It is at rest with respect to the clown and the float (both A and B)

In a diagram, the length of a vector arrow represents the

Magnitude of the vector

Who would observe the dumbbell falling backward?

Neither the clown nor child

A vector remains unchanged only when...

Only if it is moved parallel to its original direction

In the absence of air resistance, the path of a projectile is a(n)

Parabola

Which of the following may be classified as projectile motion?

Punched football, thrown baseball, water droplet cascading down a waterfall (all of the above)

What must you do to non-perpendicular vectors before you can use the Pythagorean theorem to calculate the resultant of the vectors?

Resolve the plane's displacement vectors into its x and y components

In a circus parade, a clown standing on a float moving at a constant forward speed drops a fake dumbbell. A child in the bleachers on the sidewalk observes the dumbbell. Ignore air resistance. Who would observe the dumbbell falling straight down?

The clown only

The figure below shows the motion, as seen by a stationary observer, of a stunt dummy (the black circle) as it dropped from a plane during the filming of a movie. Another plane, flying at the same velocity and altitude as the first plane, carries a camera that is filming the drop. If the camera is accidentally dropped at the moment the dummy is dropped, describe the camera's recording of the dummy's motion during its fall.

The dummy is at 0 when the camera would appear at rest.

A gardener holds the nozzle of a hose constant at a small angle above the horizontal and observes the path of the stream of water coming from the nozzle. If the pressure of the water is increased so that the water leaves the nozzle at a greater speed,

The height and width of the water's path will increase

Explain how a projectile can have a horizontal displacement even though its vertical displacement is zero.

The vertical displacement can be 0 where its caught and launched from the same position vertically. It changes horizontally so the objects move.

The clown and the child would agree about which of the following observations?

Time interval for the dumbbell to fall, vertical distance the dumbbell falls, initial velocity of the dumbbell (all of the above)

What is the major difference between a vector quantity and a scalar quantity?

Vector quantities have magnitude and distance while scalar quantity only has magnitude

Assuming no air friction and Ay=-g, the horizontal displacement of a projectile depends on the

Vertical component and the horizontal component of its initial velocity

The motion of a projectile in free fall is characterized by

Vx= constant and Ay= -g

The projection of a vector along the axes of a coordinate system is called what?

a component of the vector

Which of the displacements, when added in the order given, will yield a displacement equal to d1+d2+d3?

d2+d1+d3

In the figure...

d2=-2d4

The components of a vector are...

perpendicular

In the triangle below, what does theta equal?

tan-1(delta y/delta x)