AP Physics unit 1 review

Position

an object's place in space with respect to a reference position; a vector, so it can be negative

Velocity

an object's speed AND direction; is a vector, so it can be negative = displacement over time

Displacement

how far something ends up from its initial position

Distance

how far something travels

x vs t graphs- Greater slopes mean the object is _______

x vs t graphs- moving faster

Acceleration

a change in velocity (direction OR speed); is a vector so it can be negative = change in velocity over time

a vs t graphs- If the velocity vs. time graph is slanted, then the slope = whatever the slope is and the acceleration vs. t graph is _______

a vs t graphs- a flat line at the value of the slope

a vs t graphs- If the velocity vs. time graph is curved, then the slope is _______, and the acceleration vs. t graph is ___

a vs t graphs- constantly changing; slanted

As an object freely falls, its (a) velocity increases (b) acceleration increases (c) both of these (d) none of these

a) velocity increases

A ball is thrown upwards and caught when it comes back down. In the presence of air resistance, the speed with which it is caught is (a) more than the speed it had when thrown upwards (b) less than the speed it had when thrown upwards (c) the same as the speed it had when thrown upwards

b) less than the speed it had when thrown upwards

Which object is traveling faster? a) obj 1 b) obj 2 c) they are both traveling at the same speed d) there is not enough information obj 2 | / . | / . x(m) | / . obj 1 | / . |/.________________________look at the real graph for a better one t(s)

b) obj 2

When a rock thrown straight upwards gets to the exact top of its path, its (a) velocity is zero and its acceleration is zero (b) velocity is zero and its acceleration is about 10 m/s/s (c) velocity is about 10 m/s and its acceleration is zero (d) velocity is about 10 m/s and its acceleration is about 10 m/s/s

b) velocity is zero and its acceleration is about 10 m/s/s

acceleration vs. time graphs

Can be determined from the velocity vs. time graphs and are a graph of the slope of the velocity vs. time graphs

a vs t graphs- If the velocity vs. time graph is flat, then the slope = ___ and the acceleration vs. t graph is at ___ (one answer)

a vs t graphs- zero

The muzzle velocity of a certain gun is 100 m/s. Neglecting air resistance, at the end of one second a bullet fired straight up into the air will have traveled a distance of (a) (100 - 4.9) m (b) (100 + 4.9) m (c) 100 m (d) 4.9 m (e) none of these

a) (100 - 4.9) m

If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by about (a) 5 m/s (b) 10m/s (c) 15 m/s (d) a variable amount (e) depends on its initial speed

b) 10m/s

A group of students is designing an experiment to verify Earth's free fall acceleration rate. They plan to evacuate the air from a bell jar using a vacuum pump, and then use a remotely-controlled apparatus within the vacuum to drop a spherical metal object from rest. The group does not have a means to directly measure the sphere's acceleration rate, so they instead plan to measure other quantities about the sphere and it emotion and then will calculate an experimental value for acceleration. Which one of the following options of measurements would provide the group with enough information to determine the sphere's acceleration rate without making any unnecessary additional measurements? (a) only the drop height of the sphere (b) both the drop height and the fall time of the sphere (c) the drop height, the fall time, and the mass of the sphere (d) the drop height, fall time, and landing speed of the sphere

b) both the drop height and the fall time of the sphere

A body moving in the positive x direction passes the origin at time t = 0. Between t = 0 and t = 1 second, the body has a constant speed of 24 meters per second. At t = 1 second, the body is given a constant acceleration of 6 meters per second squared in the negative x direction. The position x of the body at t = 11 seconds is x= 24 + 24 * 10 - 1/2 * 6 * 102 (a) +99 m (b) +36 m (c) -36 m (d) -75 m (e) -99 m

c) -36 m

The graph above shows position versus time for an object moving along a straight line. During which time interval(s) is the object's speed increasing? I. 0 to 1 second II. 1 to 2 seconds III. 2 to 3 seconds (a) I only (b) II only (c) III only (d) I and III only position (m) 4-| 2-| ____ ) 0-|/___________ look at the real graph for a better one 1 2 3 time (s)

c) III only

An object moving along a straight line is slowing at a constant acceleration rate. Several data points are collected in the middle of the slowing process for the object's velocity as a function of time. The data points are shown on the graph below along with a best-fit line that has been inserted to extrapolate data for the entirety of the object's motion. In using the graph to analyze the object's motion, several different quantities about the best-fit line can be calculated. Which quantities would be equal to the objects initial velocity and to the object's displacement during its slowing motion? (a) Initial velocity- slope; Displacement- area under the line (b) Initial velocity- x-intercept; Displacement- slope (c) Initial velocity- y-intercept; Displacement- area under the line (d) Initial velocity- slope; Displacement- y-intercept velocity (m/s) |\. | \. | .\. | .\. |_______\_____________ look at the real graph for a better one t(s)

c) Initial velocity- y-intercept; Displacement- area under the line

A cart that is free to move in one dimension is moving in the positive direction and slowing down under the influence of a constant backwards pull, until the cart comes to a momentary stop and reverses direction. What are the signs of the cart's velocity and acceleration during the movement it is stopped? (a) Velocity = 0; Acceleration = + (b) Velocity = +; Acceleration = 0 (c) Velocity = 0; Acceleration = - (d) Velocity = -; Acceleration = 0

c) Velocity = 0; Acceleration = -

A bullet is dropped into a river from a very high bridge. At the same time, another bullet is fired from a gun, straight down towards the water. Neglecting air resistance, the acceleration just before striking the water (a) is greater for the dropped bullet (b) is greater for the fired bullet (c) is the same for each bullet (d) depends on how high they started

c) is the same for each bullet

Which object starts ahead of the other? (Note: the y-intercept for both lines is zero.) a) obj 1 b) obj 2 c) they both have the same starting position d) there is not enough information obj 2 | / . | / . x(m) | / . obj 1 | / . |/.________________________look at the real graph for a better one t(s)

c) they both have the same starting position

Which object moves in a positive direction? a) obj 1 b) obj 2 c) they both move in a positive direction d) there is not enough information obj 2 | / . | / . x(m) | / . obj 1 | / . |/.________________________look at the real graph for a better one t(s)

c) they both move in a positive direction

constant acceleration motion- acceleration = _______

constant acceleration motion- change in velocity / time

constant acceleration motion- Acceleration is negative if an object is _______ OR if an object is _______. If object is slowing down AND going towards more negative numbers, then acceleration is ___.

constant acceleration motion- slowing down; going towards more negative numbers; positive

constant acceleration motion- Distance covered can be found via _______ if no initial velocity

constant acceleration motion- x = 1/2 a*t2

constant velocity motion- Distance covered can be found via _______

constant velocity motion- x = v * t

The graph at right represents position x versus time t for an object being acted on by a constant force. The average speed during the interval between 1 s and 2 s is most nearly (a) 2 m/s (b) 4 m/s (c) 5 m/s (d) 6 m/s (e) 8 m/s x(m) 18-| ) 16-| ) 14-| ) 12-| ) 10-| ) 8- | ) 6- | ) 4- | ) 2- |_____._____)____________________________look at the real graph for a better one 1 2 3 t(s)

d) 6 m/s

The above graph shows velocity as a function of time for an object moving along a straight line. During which time(s) is the object at rest? I. 0.5 seconds II. From 1 to 2 seconds III 2.5 seconds (a) I only (b) II only (c) III only (d) I and III only velocity (m/s) 2-|\ / 1- | \ / 0-|--\------------/------- time (s) -1-| \ 1 2 / 3 -2| \_________/ look at the real graph for a better one

d) I and III only

Which object is traveling in a negative direction? a) obj 1 b) obj 2 c) they both are traveling in a negative direction d) neither is traveling in a negative direction obj 2 | / . | / . x(m) | / . obj 1 | / . |/.________________________ look at the real graph for a better one t(s)

d) neither is traveling in a negative direction

A group of students experiment with an object that starts from rest then moves with constant positive acceleration. As the object moves, the group measures several quantities about the object's motion. The group plots pairs of quantities in an attempt to understand relationships between their measurements. In addition to plotting quantities that they directly measured, the group also plots manipulated versions of their measured quantities. Three of the pairs of quantities listed below yield a straight-line graph for the group when they are plotted against each other. Which of the following options does not yield a straight-line graph when plotted? (a) time and speed (b) displacement and speed^2 (c) time and displacement^1/2 (d) speed and time^2

d) speed and time^2

An object is thrown with an initial speed v near the surface of Earth. Assume that air resistance is negligible and the gravitational field is constant. If the object is thrown vertically upward, the direction and magnitude of its acceleration while it is in the air is (A) upward and decreasing (B) upward and constant (C) downward and decreasing (D) downward and increasing (E) downward and constant

e) downward and constant

free fall- They have an acceleration of ___ no matter where they are in their path.

free fall- -10 m/s/s

free fall- If they are thrown up into the air and then allowed to fall, then their x vs. t graph follows _______.

free fall- a parabola

free fall- As an object is thrown up in the air, the speed _______ until it hits zero velocity at the peak of its path. It remains there for the briefest moment, and then it gets _______ to the earth as its speed gradually ___ until it hits the initial velocity it had when it was thrown up in the air. The acceleration stays the same everywhere in its path, but the velocity _______ before increasing back to its original value.

free fall- gradually decreases; pulled back down; increases; decreases to zero

free fall- Any point on one side of the parabola will _______ as the corresponding point on the other side of the parabola (same height above earth, same speed, etc.).

free fall- have the same exact characteristics

free fall- Objects are in free fall if they are _______ and the only force acting on them is _______.

free fall- in the air; gravity from the earth

free fall- ALL objects regardless of mass fall at _______ when dropped from the same height and initial velocity. The only exception to this is _______. In the real world, air pushes back against falling objects, so objects with a large area fall slower. But in a vacuum (no air), everything would land at the same time.

free fall- the same rate; air resistance

Speed

how fast something is moving = distance over time

v vs t graphs- If the position vs. time graph is slanted, then the slope = whatever the slope is and the v vs. t graph is _______

v vs t graphs- a flat line at the value of the slope

v vs t graphs- The slope of v vs. t graph

v vs t graphs- acceleration

v vs t graphs- Distance can be read off the graphs by finding the _______. Area under the curve above AND BELOW the x-axis is ___.

v vs t graphs- area under the curve; positive

v vs t graphs- Displacement can be read off the graphs by finding the _______. Area under the curve above the x-axis is ___. Area under the curve below the x-axis is ___.

v vs t graphs- area under the curve; positive; negative

v vs t graphs- Velocity is negative if graph is _______; velocity is positive if graph is _______

v vs t graphs- below axis; above axis

v vs t graphs- If the position vs. time graph is curved, then the slope is _______, and the v vs. t graph is _______

v vs t graphs- constantly changing; slanted

v vs t graphs- Object has changed direction if graph _______

v vs t graphs- crosses the x-axis

v vs t graphs- Velocity is negative if an object is going _______

v vs t graphs- towards more negative numbers

v vs t graphs- If the position vs. time graph is flat, then the slope = ___ and the v vs. t graph is at ___ (one answer)

v vs t graphs- zero

Can be determined from the position vs. time graphs and are a graph of the slope of the position vs. time graphs

velocity vs time graphs

x vs t graphs- Object has turned around if x vs. t graph has _______

x vs t graphs- a turn or bend in it

x vs t graphs- Distance can be found from the x vs. t graphs by _______

x vs t graphs- adding all the small distances together

x vs t graphs- Displacement can be read off the graphs by finding _______

x vs t graphs- how far the final position is from the initial position. yf-yi

x vs t graphs- The slope of the x vs. t graph

x vs t graphs- velocity

x vs t graphs- A flat x vs. t graph means _______; a slanted x vs. t graph means _______ at constant speed; a curved x vs. t graph means _______.

x vs t graphs- you aren't moving; you're moving; you are accelerating