Phys Lab Exam 2

A car travels 20.0 km at 90.0 degrees and then 35.0 km in a direction of 150 degrees. Find the magnitude and direction of the car's resultant displacement.

48.2 km @ 129 degrees Remember Ax = A cos(angle), Ay = A sin(angle) angle = inverse tangent of y/x. But be careful when determining the direction: Calculators almost always give the angle that is in the first quadrant (+x, +y) The correct direction is 180 - 51.1 degrees.

Given: Vector-A = 50N @ 45 degrees and Vector-B = 30N @ 120 degrees. If you graphically add Vector-A to Vector-B the best estimate of the resultant Vector-R is

65N @ 70 degrees Since both vectors are pointed upwards, their sum would be greater than 50N - 30N. The correct estimate is 65N @ 70 degrees.

If you are given that A and B are forces acting on an object and A = 3 lbs and B = 6 lbs what is the maximum force that can act on that object?

9 lbs If the forces are acting in the same direction, the largest force is 6 + 3 = 9 lbs.

The purpose of the center pin is _____________________.

To hold the ring in place while adding masses to the weight hanger

The sum of two or more vectors is called:

resultant

A quantity which can be specified by a numerical value coupled with the appropriate units is referred to as:

scalar

In the study of physics certain quantities are specified simply by stating the numerical value of the quantity along with appropriate units. Such quantities are referred to as

scalars

Which of the following types of quantities is NOT a vector?

speed

Before placing vectors on the force table, you must convert them using a scale which sets up a relationship between their __________ and ____________.

weight; length

A major source of error in this experiment is

when testing for equilibrium one fails to insure that all strings point exactly at the center of the pin

Which of the following quantities is a vector?

force

If you are given that the resultant of two vectors equals 15.0 N @ 33.0 degrees what is their equilibrant?

15.0 N @ 213 degrees

Given Vector-A is 40. N @ 53 degrees what is the magnitude of the horizontal component of Vector-A? The component is called Vector-Ax.

24

If you are given that A and B are forces acting on an object and A = 3 lbs and B = 6 lbs what is the smallest force that can act on that object?

3 lbs If the forces are acting in opposite directions, the smallest force is 6 - 3 = 3 lbs.

Given Vector-A is 40. N @ 53 degrees what is the magnitude of the vertical component of Vector-A? The component is called Vector-Ay.

32 Ay = 40sin53=32 N

Based on a graphical sketch of Vector-A equal to 50N @ 30 degrees and Vector-B equal to 50N @ 60 degrees the best estimate of the EQUILIBRANT Vector-E is

95 N @ 225 degrees The equilibrant is equal in magnitude and opposite in direction to the resultant. The answer is 95 N @ 225 degrees.

Based on a graphical sketch of Vector-A equal to 50N @ 30 degrees and Vector-B equal to 50N @ 60 degrees the best estimate of the resultant Vector-R is

95 N @ 45 degrees The direction would be between 30 degrees and 60 degrees. The correct response would be 95N @ 45 degrees.

When two or more vectors are added together, must they all have the same units?

Yes

If your weight hangers did not have an exact mass of 50.0 g (that is what you are assuming) would that affect your determination of the equilibrant?

Yes The weight of the hangers must be known because the weight of the hanger combines with the other weights on the hanger.

To experimentally verify the process of doing vector addition

a force table is used

When two force vectors are added the resultant is found experimentally by

balancing the resultant of the vectors against the equilibrant This is how you find the resultant graphically. Experimentally, you balance the resultant of the vectors against the equilibrant.

Which of the following symbol(s) can be used to indicate that a quantity is a vector?

either a bold letter or letter with an arrow above it

A vector can be split up into its x and y components

either graphically or by using sines and cosines

You balanced the orignal set of vectors with their ____________.

equilibrant

A vector which is equal in magnitude to the sum of two or more vectors but opposite in direction is referred to as:

equilibriant

The order of the addition of two or more vectors matters.

false

The purpose of this experiment is to find the resultant of a set of vectors using the notion that

the equilibriant is equal and opposite to the resultant The purpose of this experiment is to find the resultant of a set of vectors using the notion that the EQUILIBRANT is a single vector that BALANCES the vector sum. The equilibrant is equal and opposite to the resultant

Time is not a vector quantity.

true

When two force vectors are added the resultant is found experimentally by balancing the resultant of the vectors against the equilibrant.

true

A quantity which is specified by a magnitude and direction with the appropriate units is referred to as:

vector