Physics Chapter 3
Margaret walks to the store using the following path: 0.880 mi west, 0.410 mi north, 0.250 mi east. Assume north to be along the +y-axis and west to be along the -x-axis. Find the direction of the displacement vector. Enter the answer as an angle north of west
33.1° north of west
The graph of velocity (on the vertical axis) versus time (on the horizontal axis) is a horizontal line given by vx = 5 m/s. What is the displacement of the object if the initial time is 2 s and the final time is 10 s? 10 m in the +x direction 40 m in the +x direction 60 m in the +x direction 50 m in the +x direction
40 m in the +x direction
The graph of acceleration (on the vertical axis) versus time (on the horizontal axis) is a horizontal line given by ax = -5 m/s2. What is the change in velocity of the object if the initial time is 2 s and the final time is 10 s?
40 m/s in the -x direction
The graph of velocity (on the vertical axis) versus time (on the horizontal axis) is a straight line that passes through the origin and has a slope of 1 m/s2. What is the displacement of the object if the initial time is 0 s and the final time is 10 s? 100 m in the +x direction 10 m in the +x direction 50 m in the +x direction 5 m in the +x direction
50 m in the +x direction
At 3:00 P.M., a bank robber is spotted driving north on I-15 at milepost 127. His speed is 137.0 mi/h. At 3:37 P.M., he is spotted at milepost 181 doing 104.0 mi/h. (Assume a straight highway). Assume north to be positive. What is the bank robber's displacement during this time interval? Enter a positive value if the displacement is toward north and enter a negative value if the displacement is toward south.
54 mi
Salem is 45 miles south of Portland and Eugene is 45 miles south of Salem. A car is located 10 miles south of Salem. Select all of the following that fully describe the car's position. 35 miles from Eugene North of Eugene 55 miles from Portland 55 miles south of Portland South of Portland 35 miles north of Eugene
55 miles south of Portland 35 miles north of Eugene
Choose all the correct statements about distance and displacement. -Distance traveled is always the magnitude of the displacement vector. -The distance traveled can never be more than the displacement. -Distance is a scalar and displacement is a vector. -The displacement can never be more than the distance traveled.
Distance is a scalar and displacement is a vector. The displacement can never be more than the distance traveled. NOTES: Distance traveled is always the magnitude of the displacement vector. ~The magnitude of the displacement vector would be how far away something is from where it started as measured by a straight line. In general, this is not the same as distance traveled. The distance traveled can never be more than the displacement. ~If the path includes turns or doubling back, then the distance will be greater than the displacement.
A walker starts at the origin at 1:00 PM and walks 3.0 km from the origin toward the WEST to poin... A walker starts at the origin at 1:00 PM and walks 3.0 km from the origin toward the WEST to point A. She arrives at point A at 2:30 PM. She then walks from point A, 2.0 km toward the WEST to point B and arrives at point B at 3:45 PM. The walker's average velocity for the entire trip is_____?
Distance traveled: 3 km + 2 km = 5 km Direction of travel: to the west Duration of travel: 3:45 - 1:00 = 2:45 = 2.75 hours Average velocity = 5 / 2.75 = 1.82 km per hour toward the west.
The graph of position (plotted on the vertical axis) versus time (plotted on the horizontal axis) is a parabola that opens upward and passes through the origin. Select all of the following that correctly describe the velocity when t > 0.
increasing and positive
An experiment involving two objects produces the acceleration versus net force graphs shown in the image. How are the masses of the two objects related? m1 > m2 m1 < m2 m1 = m2
m1 > m2
Alice will go to the store by traveling 3 miles east and then 4 miles south. The distance she travels is ________ miles, but her displacement is only __________ miles south-east.
seven and five
The net force acting on an object over a time interval is shown by the net force versus time graph in the image. The object was moving in the positive x-direction at time t0. At which time is the object's speed a maximum? t1 The object's speed does not change. t2 t0
t2
If an object is moving to the right and is experiencing a net force to the left, then the acceleration is to the left.
true
How many pieces of information are needed to specify the position of an object? -2 -3 -1 -4
3
If the first displacement is (10 meters, 30 degrees east of south) and the second displacement is (10 meters, 30 degrees east of north) of the origin, then what is the total displacement? (8.7 meters, east) (30 meters, east) (20 meters, east) (10 meters, east) (40 meters, east)
(10 meters, east)
A car travels around a circular track clockwise (as viewed from above) at constant speed. Its initial position is at the northern end of the circle, and its final position is at the southern end of the circle. The radius of the track is 500 m, and it took the car 50 seconds to travel from its initial position to its final position. What was the average velocity of the car? 20.0 m/s (31.4 m/s, south) 31.4 m/s (20.0 m/s, south)
(20.0 m/s, south)
The following pairs of displacements represent the first and second parts of three different trips. Rank the trips in order of the total displacement magnitude, with the largest total displacement magnitude at the top and the smallest total displacement magnitude at the bottom.
(40 m, east) and (40 m, east) (50 m, east) and (40m west) (50 m, east) and (50m west)
A car travels along city streets at constant speed. First, it travels 200 m north. Second, it travels 200 m east. Third, it travels 200 m south. It took the car 40 seconds to travel from its initial position to its final position. What was the average velocity of the car? (15.0 m/s, east) 5.00 m/s 15.0 m/s (5.00 m/s, east)
(5.00 m/s, east)
If the initial position is (40 meters, southwest) of the origin, and the final position is (50 meters, northeast) of the origin, what is the displacement? Note: Southwest is exactly halfway between south and west, and northeast is exactly halfway between north and east. (10 meters, northeast) (90 meters, southwest) (10 meters, southwest) (90 meters, northeast)
(90 meters, northeast)
An accelerometer—a device to measure acceleration—can be as simple as a small pendulum hanging in an airplane cockpit. An essentially similar accelerometer is found in the inner ear of vertebrates. Suppose you are flying a small plane in a straight, horizontal line and your accelerometer hangs at a constant angle of P = 19.3° behind the vertical, as shown in the figure. What is your acceleration? Enter a positive answer if the acceleration is in the direction of motion and enter a negative answer if the acceleration is opposite to the direction of motion.
3.42
Select all of the following that are equivalent to displacement. - Select all of the following that are equivalent to displacement. - Final position minus initial position - Initial position minus final position -Sum of the initial position and the opposite of the final position
- Select all of the following that are equivalent to displacement. - Final position minus initial position
An acceleration versus time graph shows a straight line that passes through zero with a slope of --1 m/s2. What is the change in velocity from 0 seconds to 2 seconds? 1 m/s 4 m/s 2 m/s --4 m/s --1 m/s --2 m/s
--2 m/s
An object is thrown upward from 1 m above the ground. It travels vertically up, reaches a maximum height of 2.5 m above ground, falls back down, and is caught at exactly the same position it was thrown 1 s after it was thrown. What was the average velocity of the object? 3 m/s 0 m/s 1.5 m/s
0 m/s
The displacement is (40 m, 30 degrees north of east), and the time interval is 20 s. The +x-axis points to the east, and the +y-axis points to the north. What is the y-component of the average velocity? 1.00 m/s 2.00 m/s 1.73 m/s
1.00 m/s
An object traveling along the x-axis has a velocity of 2.0 m/s from 0 to 4.0 s, 0 m/s from 4.0 to 6.0 s, -2.0 m/s from 6.0 to 8.0 s, and 4.0 m/s from 8.0 to 10 s. What is the average velocity of the object from 0 to 10 s?
1.2 m/s NOTES To find the average velocity, determine the displacement for each time interval by multiplying each velocity by the length of time traveled at that velocity, add the displacements, and then divide by the total time (10 s).
If the first displacement is (10 meters, 30 degrees east of south) and the second displacement is (10 meters, 30 degrees east of north) of the origin, then what is the total displacement? (30 meters, east) (10 meters, east) (8.7 meters, east) (20 meters, east) (40 meters, east)
10 meters, east
The airport is located at the origin. To the west is the -x direction and to the east is the +x direction. Rank the following positions, with the largest position magnitude at the top and the smallest position magnitude at the bottom.
10 miles east of the airport 8 miles west of the airport 5 miles east of the airport 4 miles west of the airport
A bicycle travels 7.40 km due east in 0.760 h, then 4.90 km at 15.0° east of north in 0.810 h, and finally another 7.40 km due east in 0.760 h to reach its destination. The time lost in turning is negligible. Assume that east is in the +x-direction and north is in the +y-direction. What is the direction of the average velocity for the entire trip? Enter the answer as an angle in degrees north of east.
16.4° north of east
A jetliner flies east for 670.0 km, then turns 30.0° toward the south and flies another 171 km. Moving at a constant speed of 400.0 km/h, how long would the direct flight have taken?
2.06h
The peak force on a runner's foot during a race is found to be vertical and three times his weight. What is the peak force on the foot of a runner whose mass is 80.0 kg? If the peak force is upward, enter a positive value. If the peak force is downward, enter a negative value.
2.35 kN
In a movie, a stuntman places himself on the vertical front of a truck as the truck accelerates. The coefficient of static friction between the stuntman and the truck is 0.170. The stuntman is not standing on anything but can "stick" to the front of the truck as long as the truck continues to accelerate. What minimum forward acceleration will keep the stuntman on the front of the truck?
57.7 m/s^2
A small plane is flying directly west with an airspeed of 38.0 m/s. The plane flies into a region where the wind is blowing at 10.0 m/s at an angle of 30.0° to the south of west. Assume north to be in the +y-direction and east to be in the +x-direction. What will be the new course, relative to the ground, of the airplane? Enter an angle in degrees south of west.
6.12° south of west
A 2.00-kg toy locomotive is pulling a 1.00-kg caboose. The frictional force of the track on the caboose is 0.500 N backward along the track. If the train's acceleration forward is 6.10 m/s2, what is the magnitude of the force exerted by the locomotive on the caboose?
6.60N
The diagram shows a boat crossing a stream. Toward which point could the skipper aim the boat so that it would travel to point Z? B A C
A
Select all of the following statements regarding motion diagrams and graphs that are true. A motion diagram is just another name for a graph of position versus time. A motion diagram can be used to create a graph of position versus time. A graph of position versus time can be used to create a motion diagram.
A motion diagram can be used to create a graph of position versus time. A graph of position versus time can be used to create a motion diagram.
Which of the following is an inertial reference frame? ~A reference frame attached to an object rotating with constant speed where the gravitational field is negligibly small ~A reference frame attached to an object rotating with nonconstant speed where the gravitational field is negligibly small ~A reference frame in which the net force on an object is zero if and only if the object's acceleration is zero
A reference frame in which the net force on an object is zero if and only if the object's acceleration is zero
The motion diagram for an object moving along a straight line consists of dots that are equally spaced, that is, the distance between adjacent dots is constant. Select all of the position versus time graphs below that could possibly correspond to this motion diagram. Position is plotted on the vertical axis, and time is plotted on the horizontal axis. A straight line with a slope of 10 m/s that does not pass though the origin A straight line with a slope of 10 m/s that passes though the origin A horizontal line that does not pass through the origin
A straight line with a slope of 10 m/s that does not pass though the origin A straight line with a slope of 10 m/s that passes though the origin
Three people on the ground are each doing something different. Alice is walking towards the West at 2 mph, Bob is sitting on the ground, and Carol is jogging to the East at 8 mph. If Evan is driving East at 25 mph, which person has the greatest speed relative to him? Carol Alice Bob
Alice
Match the quantity of the left with its numerical value on the right, given that the change in velocity is (40 m/s, 30 degrees north of east), and the time interval is 20 s. The +x-axis points to the east, and the +y-axis points to the north. Average acceleration = x-component of the average acceleration= y-component of the average acceleration =
Average acceleration = matches (2.0 m/s2, 30 degrees north of east)(2.0 m/s2, 30 degrees north of east) x-component of the average acceleration= matches +1.73 m/s2+1.73 m/s2 y-component of the average acceleration = +1.00 m/s2
Two vectors have the same magnitude. Vector A points to the east and vector B points to the north. Vector C is equal to vector A minus vector B. What is the direction of vector C? -Between south and west -Between south and east -Between north and west -Between north and east
Between south and east
A car travels around a circular track clockwise (as viewed from above). When the car is located at the east end of the circle, what is the direction of its velocity?
South
Select all of the following that have the same direction as the average velocity. Final position minus initial position Displacement Initial position minus final position
Final position minus initial position Displacement
Select all of the following that have the same direction as the average acceleration. Final velocity minus initial velocity Change in velocity Initial velocity minus final velocity
Final velocity minus initial velocity Change in velocity
Sidney Crosby of the Pittsburgh Penguins has just hit a hockey puck with his hockey stick, and the puck is sliding on a rough patch of ice several feet in front of the stick. Select all of the following forces that act on the puck in this scenario. Friction Tension Normal force Force of the stick Gravitational force
Friction Normal force Gravitational force
A block is pulled up a rough surface, as shown. Select all of the forces that act on the block. Pull force Gravitational force Normal force Tension Friction
Gravitational force Normal force Tension Friction
The graph of position (plotted on the vertical axis) versus time (plotted on the horizontal axis) is a parabola that opens upward and passes through the origin. Select all of the following that correctly describe the velocity when t > 0. Constant Decreasing Negative Increasing
Increasing Positive
The graph of velocity (plotted on the vertical axis) versus time (plotted on the horizontal axis) is a parabola that opens upward and passes through the origin. Select all of the following that could be the acceleration when t > 0. Decreasing increasing Negative Constant positive
Increasing and positive
Match the variable on the left with the graphical information on the right. Instantaneous acceleration Average acceleration Instantaneous velocity Average velocity
Instantaneous acceleration ~ The slope of the tangent line at a point on a graph of velocity versus time Average acceleration ~ The slope of the chord connecting two points on a graph of velocity versus time Instantaneous velocity ~ The slope of the tangent line at a point on a graph of position versus time Average velocity ~ matches The slope of the chord connecting two points on a graph of position versus time
Match the quantity on the left with the graphical interpretation on the right. Instantaneous velocity= Average Velocity =
Instantaneous velocity= The slope of the tangent line at a point on a graph of position versus time Average Velocity = The slope of the chord connecting two points on a graph of position versus time
Select all of the following that occur to a vector when it is multiplied by the scalar negative one. Its direction is reversed. Its direction stays the same. Its magnitude is multiplied by negative one. Its magnitude stays the same.
Its direction is reversed. Its magnitude stays the same.
Rank the following quantities with the largest at the top and the smallest at the bottom, given that the displacement is (40 m, 30 degrees north of east) and the time interval is 20 s. The +x-axis points to the east, and the +y-axis points to the north.
Magnitude of the average velocity x-component of the average velocity y-component of the average velocity
To which of the following is an object's acceleration inversely proportional, assuming the other two quantities remain constant? Mass Net force Velocity
Mass
Relate the quantity on the left with its dependence on position on the right. Mass= Weight=
Mass = Does not depend on the objects position Weight = Does depend on the objects position
Relate the quantity on the left with its description on the right. Mass= Weight=
Mass= A measure of an object's inertia Weight= The magnitude of the gravitational force on an object correct
A tractor T is pulling two trailers, M1 and M2, with a constant acceleration. T has a mass of 200 kg, M1 has a mass of 100 kg, and M2 has a mass of 150 kg. If the forward acceleration is 0.60 m/s2, then the horizontal force on the tractor due to the ground is
Net Force = Net mass x acceleration = (200+100+150) x 0.6 = 450 x 0.6 = 270 Newtons ( in forward direction) Hence Option- B is correct !!!
Which of Newton's laws identifies an inertial reference frame? Newton's Second Law Newton's Third Law Newton's First Law Newton's Law of Universal Gravitation.
Newton's First Law
If an object's acceleration is in the -x direction, which statement is always true? The object is slowing down. The object's speed is negative. None of the statements is always true. The object is moving in the -x direction. The object is speeding up.
None of the statements is always true
A car travels around a circular track counterclockwise (as viewed from above). When the car is located at the east end of the circle, what is the direction of its velocity?
North
Which of the following elements is necessary to draw a motion diagram?
Positions of the object at equally spaced times
Acceleration is the ______ at a point on the velocity versus time graph, and the change in ______ is the area under the curve on the acceleration versus time graph.
Slope and Velocity
The difference of two vectors is equal to the zero vector. Select all statements that are true. The two vectors point in opposite directions. The two vectors point in the same direction. The two vectors have different magnitudes. The two vectors are perpendicular. The two vectors have the same magnitude.
The two vectors point in the same direction. The two vectors have the same magnitude.
Three rectangular boxes are stacked vertically, and the combination is placed on a table. The surface of the table is horizontal. The table rests on the surface of the Earth. All three boxes and the table are stationary and remain stationary with respect to the surface of the Earth. Select all of the following statements that are true. Ignore any forces caused by the air around the boxes and table. There are three forces acting on the top box. There are three forces acting on the bottom box. There are three forces acting on the table. There are three forces acting on the middle box.
There are three forces acting on the bottom box. There are three forces acting on the table. There are three forces acting on the middle box.
Which of the following is Newton's second law? Fnet−→−− = v→m Fnet−→−− = m v→ Fnet−→−− = a→m a→ = Fnet−→−−m
a→ = Fnet−→−−m
Consider the position versus time graph. Select all of the following that correctly describe the velocity.
constant and positive
A car traveling at 3.0 m/s has a constant acceleration of 4.0 m/s2. After 2.0 seconds, the velocity is A) 5.0 m/s. B) 7.0 m/s. C) 9.0 m/s. D) 11 m/s. E) 13 m/s.
d = vi + (1/2)at^2 100 = 0 + (1/2)(a)(10^2) 100 = 50a, a = 2 m/s^2 choice B
Velocity is the rate of change of acceleration. true or false
false
