Physics Test 3

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 to the road. As the first car approaches you, what is its velocity relative to you?

+2VCAR

The water used in many fountains is recycled. For instance, a single water particle in a fountain travels through an 85 m system and then returns to the same point.What is the displacement of this water particle during one cycle?

0

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

A component of a vector

Do you add or subtract if two objects are going the opposite direction with earth as the frame of reference?

Add

What do you do when you need to subtract a vector?

Add its opposite

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

At the highest point of the ball's path

What is an example of vector quantity?

Average velocity (includes direction)

Which of the following may be classified as projectile motion? a. a punted football b. a thrown baseball c. a water droplet cascading down a waterfall d. all of the above

D.

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

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

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 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. only (Ask Mrs Hopper)

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

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

What is an example of scalar quantity?

Number of pages in a book (no direction)

The components of a vector are..?

Perpendicular

What can two vectors not do?

Start from the same point.

Do you add or subtract if two objects are going the same direction with earth as the frame of reference?

Subtract

A plane that is flying plans to drop a dummy. The plane also 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's motion compared to the camera would be zero. The dummy would appear to be at rest with respect to the camera.

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

The vertical component and the horizontal component of its initial velocity.

What is the relative velocity formula?

Vac = Vab + Vbc

What's a major difference between a vector quantity and a scalar quantity?

Vector quantity includes magnitude and direction, but scalar quantity includes just magnitude

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

You have to divide them into components that are perpendicular.

Vector quantity

a physical quantity that has both magnitude and direction

Scalar quantity

a physical quantity that measures magnitude but not direction

What is a frame of reference?

a position from which an observer measures velocity

10. Which of the following exhibit parabolic motion? a. a flat rock skipping across the surface of a lake b. a three-point shot in basketball c. the space shuttle while orbiting Earth d. a ball bouncing across a room e. a life preserver dropped from a stationary helicopter

a, b, d

Which of the following is a frame of reference for measuring motion? a. coordinate system b. diagram c. graph d. none of the above

a.

Which of the following quantities are scalars, and which are vectors? a. the acceleration of a plane as it takes off b. the number of passengers on the plane c. the duration of the flight d. the displacement of the flight e. the amount of fuel required for the flight

a. vector b. scalar c. scalar d. vector e. scalar

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

have a horizontal component

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

have a horizontal component.

In the absence of air resistance, the path of a projectile is what shape...?

parabola

Resultant Vector

the dotted line that represents the sum of two or more vectors

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.

The motion of a projectile in free fall is characterized by...?

vx = constant and ay = -g.