Holt Physics 3

A boat travels directly across a river that has a downstream current, v. What is true about the perpendicular components of the boat's velocity?

One component is perpendicular to v; the other component equals -v

What is the path of a projectile?

parabola

A student walks from the door of the house to the end of the driveway and realizes that he missed the bus. The student runs back to the house, traveling three times as fast. Which of the following is the correct expression for the return velocity if the initial velocity is vstudent?

-3Vstudent

A hiker undergoes a displacement of d5 as shown in the figure above. A single displacement that would return the hiker to his starting point would have which of the following sets of components?

-d5,x; -d5,y

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 of the following statements is true? 1. Both balls strike the ground at the same time 2. The dropped ball reaches the ground first 3. The knocked ball reaches the ground first 4. Both balls strike the ground at the same speeds

1 only

A cave explorer travels 3.0 m eastward, then 2.5 m northward, and finally 15 m westward. Use the graphical method to find the magnitude of the net displacement.

12.2 m

A stone is thrown at an angle of 30° above the horizontal form the top edge of a cliff with an initial speed of 12m/s. A stopwatch measures the stones trajectory time from the top of the cliff to the bottom at 5.6s. What is the height of the cliff?

120m

In a movie production, a stunt person must leap from a balcony of one building to a balcony 3 m lower on another building. If the buildings are 2m apart, what is the minimum horizontal velocity the stunt person must have to accomplish the jump?

2.6 m/s

Find the resultant of these two vectors: 2.00x10^2 units due east and 4.00x10^2 units 30° north of west

248 units 53.9° north of west

A small airplane flies at a velocity of 145 km/h toward the south as observed by a person on the ground. The airplane pilot measures an air velocity of 172 km/h south. What is the velocity of the wind that affects the plane?

27 km/hr north

an ant on a picnic table travels 3.0x10^1 cm eastward, then 25 cm northward, and finally 15 cm westward. What is the magnitude of the ant's displacement relative to its original position

29 cm

How many displacement vectors shown in the figure above have horizontal components?

4

A jet moving at 500.0 km/h due east is in a region where the wind is moving at 120.0 km/h in a direction 30.00° north of east. What is the speed of the aircraft relative to the ground?

606.9 km/h

A track star in the long jump goes into the jump at 12 m/s and launches herself at 20.0 degrees above the horizontal. What is the magnitude of her horizontal displacement?

9.2m

Which of the following exhibits parabolic motion?

A stone thrown in a lake

At what point of the ball's path shown in the figure above is the vertical component of the ball's velocity zero?

B

Briefly explain the triangle method of addition

It requires that you align the vectors, one after the other, tail to nose, by moving them parallel and perpendicular to their original orientations. The resultant vector is an arrow drawn from the tail of the first vector to the tip of the last vector

Briefly explain why a basketball being thrown toward a hoop is considered projectile motion

Objects sent into the air and subject to gravity exhibit projectile motion

The equation D= the square root of deltaX squared + deltaY squared is only valid if deltaX and deltaY are magnitudes of vectors that have what orientation with respect to each other?

The vectors must be perpendicular to each other

The motion of a projectile in free fall is characterized by

Vx= constant and Ay= -g

Which of the following does NOT exhibit parabolic motion?

a flat piece of paper released from a window

Which of the following may be classified as projectile motion?

a punted football, a thrown baseball, a water droplet cascading down a waterfall

Which of the following is an example of projectile motion?

a thrown baseball

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

at the highest point of its path

In the figure above, which diagram represents the vector addition, C= A + B

b. II

In a coordinate system, a vector is oriented at angle Ø with respect to the x-axis. The x component of the vector equals the vector's magnitude multiplied by which trigonometric function?

cosØ

In the figure above, which diagram represent vector subtraction?

d. IV

Which displacement vectors shown in the figure have vertical components that are equal?

d1 and d3

Is distance or displacement a vector quantity?

displacement

In a coordinate system, the magnitude of the x compound of a vector and Ø, the angle between the vector and x-axis, are known. The magnitude of the vector equal the x component

divide by the cos of Ø

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

have a horizontal component

Explain how a projectile can have a horizontal displacement even though it's vertical displacement is zero

if the object is launched and caught from the same initial vertical position, it's vertical displacement is zero because it was moving first up and then down the same distance while moving horizontally during its flight

A passenger on a bus moving east sees a man standing on a curb. From the passenger's perspective, the man appears to

move west at a speed that is equal to the bus's speed

How can you use the Pythagorean theorem to add two vectors that are not perpendicular

resolve each vector into perpendicular components and add the components that lie along the same axis. The resultant vectors can be added by using the Pythagorean theorem because they are perpendicular

Which of the following is a physical quantity that has a magnitude but no direction?

scalar

Identify the following quantities as scalar or vector: the mass of an object, the number of leaves on a tree, wind velocity.

scalar, scalar, vector

A piece of chalk is dropped by a teacher walking at a speed of 1.5 m/s. From the teacher's perspective, the chalk appears to fall

straight down

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

If the magnitude of a vector component equals the magnitude of the vector, then what is the magnitude of the other vector component?

the magnitude of the other component vector is zero

Multiplying or dividing vectors by scalars results in

vectors

Which of the following is an example of a vector quantity?

velocity

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