Mastering Physics Midterm
You are standing on a straight stretch of road and watching the motion of a bicycle; you choose your position as the origin. At one instant, the position of the bicycle is negative and its velocity is positive. Is the bicycle getting closer to you or farther away? Explain.
If the position of the bicycle is negative it is to your left. The bicycle's velocity is positive, or to the right, so the bicycle is getting closer to you.
Determine the sign (positive or negative) of the position and the velocity for the motion diagram in (Figure 2)?
Negative position, negative velocity
Determine the sign (positive or negative) of the position and the velocity for the motion diagram in (Figure 1)?
Negative position, positive velocity
For each motion diagram shown in the figure, determine the sign (positive or negative) of the acceleration. (Figure 1) B
Negative.
For each motion diagram shown in the figure, determine the sign (positive or negative) of the acceleration. (Figure 1) C
Negative.
Does a real automobile have constant acceleration? Measured data for a Porsche 944 Turbo at maximum acceleration are as follows: Based on your graph, is the acceleration constant?
No, it decreases with increasing time
Determine the sign (positive or negative) of the position and the velocity for the motion diagram in (Figure 3)?
Positive position, negative velocity
For each motion diagram shown in the figure, determine the sign (positive or negative) of the acceleration. (Figure 1) A
Positive.
A car travels along a straight east-west road. A coordinate system is established on the road, with x increasing to the east. The car ends up 13 mi west of the intersection with Mulberry Road. If its displacement was -27 mi , how far from Mulberry Road did it start? On which side of Mulberry Road did it start?
The car started 11 mi east of Mulberry Road.
An object moves along the x axis during four separate trials. Graphs of position versus time for each trial (with the same scales on each axis) are shown in the figure. During which trial or trials is the object's velocity not constant?
Trial B
An object moves along the x axis during four separate trials. Graphs of position versus time for each trial (with the same scales on each axis) are shown in the figure. During which trial or trials is the magnitude of the average velocity the largest?
Trial B and Trial D
The bacterium Escherichia coli (or E. coli), is a single-celled organism that lives in the gut of healthy humans and animals. When grown in a uniform medium rich in salts and amino acids, it swims along zig-zag paths at a constant speed. (Figure 1) shows the positions of an E. coli as it moves from point A to point J. Each segment of the motion can be identified by two letters, such as segment BC. During which segments, if any, does the bacterium have the same speed?
all paths
Which of the quantities are zero throughout the flight?
ax
A ball is thrown straight up into the air. At each of the following instants, is the ball's acceleration ay equal to g, −g, 0, <g, or >g? At the very top max height
ay=−g
A ball is thrown straight up into the air. At each of the following instants, is the ball's acceleration ay equal to g, −g, 0, <g, or >g? Just after leaving you hand
ay=−g
A ball is thrown straight up into the air. At each of the following instants, is the ball's acceleration ay equal to g, −g, 0, <g, or >g? Just before hitting the ground
ay=−g
Give an example of a trip you might take in your car for which the distance traveled as measured on your car's odometer is not equal to the displacement between your initial and final positions.
circular motion with a constant speedlinear motion with acceleration
A student at the top of a building of height h throws ball A straight upward with speed v0 and throws ball B straight downward with the same initial speed. Compare the ball's accelerations, both direction and magnitude, immediately after they leave her hand. Is one acceleration larger than the other? Or are the magnitudes equal?
equal
A student at the top of a building of height h throws ball A straight upward with speed v0 and throws ball B straight downward with the same initial speed. Compare the final speeds of the balls as they reach the ground.
equal
The figure below shows an object's position-versus-time graph. The letters A to E correspond to various segments of the motion in which the graph has constant slope. (Figure 1) Is the speed of the object during segment C greater than, equal to, or less than its speed during segment E?
greater
One consequence of Einstein's theory of special relativity is that mass is a form of energy. This mass-energy relationship is perhaps the most famous of all physics equations:E=mc2,where m is mass, c is the speed of the light, and E is the energy. In SI units, the units of speed are m/s. For the preceding equation to have consistent units (the same units on both sides of the equation), the units of E must be which of the following?
kg⋅m2 / s2
A man rides a bike along a straight road at a constant speed for 5 minmin, then has a flat tire. He stops for 5 minmin to repair the flat, but then realizes he cannot fix it. He continues his journey by walking the rest of the way at a constant speed, which takes him another 10 min. Select a correct motion diagram of the man for the entire motion described here.
0 1 2 3 4 5 11 12 13 14 15 16 17 18 19
When you blink your eye, the upper lid goes from rest with your eye open to completely covering your eye in a time of 0.024 s. What is your upper eyelid's final speed as it hits the bottom eyelid?
0.84 m/s
When you blink your eye, the upper lid goes from rest with your eye open to completely covering your eye in a time of 0.024 s. Estimate the distance that the top lid of your eye moves during a blink.
1 cm
The bacterium Esch- B0 erichia coli (or E. coli) is a single-celled organism that lives in the gut of healthy humans and animals. Its body shape can be modeled as a 2-um-long cylinder with a 1 um diameter, and it has a mass of 1 x 10-12 g. Its chromosome consists of a single double-stranded chain of DNA 700 times longer than its body length. The bacterium moves at a constant speed of 20 μm/s, though not always in the same direction. Answer the following questions about E. coli using SI base units (unless specifically requested otherwise) and correct significant figures. What is the length of its DNA, in millimeters?
1 mm
The bacterium Esch- B0 erichia coli (or E. coli) is a single-celled organism that lives in the gut of healthy humans and animals. Its body shape can be modeled as a 2-um-long cylinder with a 1 um diameter, and it has a mass of 1 x 10-12 g. Its chromosome consists of a single double-stranded chain of DNA 700 times longer than its body length. The bacterium moves at a constant speed of 20 μm/s, though not always in the same direction. Answer the following questions about E. coli using SI base units (unless specifically requested otherwise) and correct significant figures. What is its mass?
1 x 10^-15 kg
Weddell seals make holes in sea ice so that they can swim down to forage on the ocean floor below. Measurements for one seal showed that it dived straight down from such an opening, reaching a depth of 0.30 km in a time of 5.0 min What was the speed of the diving seal?
1.0 m/s
A rectangle has length 3.24 m and height 0.432 m. To the correct number of significant figures, what is its area?
1.40 m^2
The Earth Formed 4.57 X 10^9 Years Ago. What Is This Time In Seconds?
1.44 x 10^17 s
A person walks briskly at 2.10 m/s. How much time will it take them to walk one mile?
12.8 min
A car can go from 0 to 60 mph in 14 s. A second car is capable of twice the acceleration of the first car. Assuming that it could maintain the same acceleration at higher speeds, how much time will this second car take to go from 0 to 120 mph?
14 s
A car can go from 0 to 60 mph in 8.0 s. Assuming that it could maintain the same acceleration at higher speeds, how long would it take the car to go from 0 to 120 mph?
16 s
Riders on a Ferris wheel move in a circle with a speed of 4.50 m/s . As they go around, they experience a centripetal acceleration of 2.40 m/s^2 . What is the diameter of this particular Ferris wheel?
16.9 m
A cannon, elevated at 40∘ is fired at a wall 300 m away on level ground, as shown in the figure below. The initial speed of the cannonball is 89 m/s.(Figure 1) At what height h does the ball hit the wall?
160 m
On the earth, an astronaut throws a ball straight upward; it stays in the air for a total time of 3.1 s before reaching the ground again. If a ball were to be thrown upward with the same initial speed on the moon, how much time would pass before it hit the ground?
19s
The bacterium Esch- B0 erichia coli (or E. coli) is a single-celled organism that lives in the gut of healthy humans and animals. Its body shape can be modeled as a 2-um-long cylinder with a 1 um diameter, and it has a mass of 1 x 10-12 g. Its chromosome consists of a single double-stranded chain of DNA 700 times longer than its body length. The bacterium moves at a constant speed of 20 μm/s, though not always in the same direction. Answer the following questions about E. coli using SI base units (unless specifically requested otherwise) and correct significant figures. What is its diameter?
1x 10^-6 m
The bacterium Esch- B0 erichia coli (or E. coli) is a single-celled organism that lives in the gut of healthy humans and animals. Its body shape can be modeled as a 2-um-long cylinder with a 1 um diameter, and it has a mass of 1 x 10-12 g. Its chromosome consists of a single double-stranded chain of DNA 700 times longer than its body length. The bacterium moves at a constant speed of 20 μm/s, though not always in the same direction. Answer the following questions about E. coli using SI base units (unless specifically requested otherwise) and correct significant figures. If the organism were to move along a straight path, how many meters would it travel in one day?
2 m
The bacterium Esch- B0 erichia coli (or E. coli) is a single-celled organism that lives in the gut of healthy humans and animals. Its body shape can be modeled as a 2-um-long cylinder with a 1 um diameter, and it has a mass of 1 x 10-12 g. Its chromosome consists of a single double-stranded chain of DNA 700 times longer than its body length. The bacterium moves at a constant speed of 20 μm/s, though not always in the same direction. Answer the following questions about E. coli using SI base units (unless specifically requested otherwise) and correct significant figures. What is its length?
2 x 10^-6 m
A student walks 1.6 mi west and then 1.6 mi north. Afterward, how far is she from her starting point?
2.3 mi
A bird flies 3.6 km due west and then 2.1 km due north. Another bird flies 2.1 km due west and 3.6 km due north. What is the angle between the net displacement vectors for the two birds?
29 degrees
A football is kicked at an angle of 40 ∘ with a speed of 24 m/s . To the nearest second, how long will the ball stay in the air
3 s
The figure shows an object's position-versus-time graph. (Figure 1) What is the velocity of the object at 6 s ?
3.3 m/s
When you blink your eye, the upper lid goes from rest with your eye open to completely covering your eye in a time of 0.024 s. What is the acceleration of your eyelid? Assume it to be constant.
3.5 x 10^1 m/s^2
If an astronaut can jump straight up to a height of 0.5m on earth, how high could he jump on the moon?
3.6 m
Compute 3.24 m + 0.432 m to the correct number of significant figures.
3.67 m
A cannon, elevated at 40∘ is fired at a wall 300 m away on level ground, as shown in the figure below. The initial speed of the cannonball is 89 m/s.(Figure 1) How long does it take for the ball to hit the wall?
4.4 s
A bird flies 3.8 km due west and then 2.4 km due north.
4.5 km
Motor neurons in mammals transmit signals from the brain to skeletal muscles at approximately 25 m/s Estimate how much time in ms (10e−3 s) it will take for a signal to get from your brain to your hand.
40 ms
Suppose a plane accelerates from rest for 30 s, achieving a takeoff speed of 80 m/s after traveling a distance of 1200 m down the runway. A smaller plane with the same acceleration has a takeoff speed of 56 m/s. Starting from rest, after what distance will this smaller plane reach its takeoff speed?
588 m
An objects average density (p) is defined as the ratio of its mass to its volume . The earths mass is 5.94 x 10^24 kg and its volume is 1.08 x 10^12 km3. What is the earths average density?
5x5 x 10^3 kg/m^3
The images of trees in the figure come from a catalog advertising fast-growing trees. If we mark the position of the top of the tree in the successive years, as shown in the graph in the figure, we obtain a motion diagram much like ones we have seen for other kinds of motion. The motion isn't steady, of course. In some months the tree grows rapidly; in other months, quite slowly. We can see, though, that the average speed of growth is fairly constant for the first few years.(Figure 1) At the end of year 3, a rope is tied to the very top of the tree to steady it. This rope is staked into the ground 15 feet away from the tree. What angle does the rope make with the ground?
63
A jogger running east at a steady pace suddenly develops a cramp. He is lucky: A westbound bus is sitting at a bus stop just ahead. He gets on the bus and enjoys a quick ride home. Use the particle model to draw a motion diagram of the jogger for the entire motion described here. Number the dots in order, starting with zero.
7 6 5 0 1 2 3 4
On the earth, an astronaut can safely jump to the ground from a height of 1.3 m ; her velocity when reaching the ground is slow enough to not cause injury. From what height could the astronaut safely jump to the ground on the moon?
7.8 m
A car is traveling at v_x = 24 m/s. The driver applies the brakes and the car decelerates at a_x = -4.0 m/s^2 . What is the stopping distance?
72 m
The images of trees in the figure come from a catalog advertising fast-growing trees. If we mark the position of the top of the tree in the successive years, as shown in the graph in the figure, we obtain a motion diagram much like ones we have seen for other kinds of motion. The motion isn't steady, of course. In some months the tree grows rapidly; in other months, quite slowly. We can see, though, that the average speed of growth is fairly constant for the first few years.(Figure 1) What is the tree's speed of growth, in feet per year, from t=1yr to t=3yr?
9 ft/yr
Gravity causes objects to be attracted to one another. This attraction keeps our feet firmly planted on the ground and causes the moon to orbit the Earth. The force of gravitational attraction is represented by the equationF=Gm1m2r2, where F is the magnitude of the gravitational attraction on either body, m1 and m2 are the masses of the bodies, r is the distance between them, and G is the gravitational constant. In SI units, the units of force are kg⋅m/s2, the units of mass are kg, and the units of distance are m. For this equation to have consistent units, the units of G must be which of the following?
m^3 / kg⋅s2
The images of trees in the figure come from a catalog advertising fast-growing trees. If we mark the position of the top of the tree in the successive years, as shown in the graph in the figure, we obtain a motion diagram much like ones we have seen for other kinds of motion. The motion isn't steady, of course. In some months the tree grows rapidly; in other months, quite slowly. We can see, though, that the average speed of growth is fairly constant for the first few years.(Figure 1) What is the tree's speed in m/s?
9 x 10^-8 m/s
The figure below shows an object's position-versus-time graph. The letters A to E correspond to various segments of the motion in which the graph has constant slope. (Figure 1) In which segment(s) is the object moving to the right (in the positive x direction)?
A
Two cars travel on the parallel lanes of a two-lane road. The cars' motions are represented by the position versus time graph shown in the figure. Answer the questions using the times from the graph indicated by letters. At which of the lettered times are the cars moving with nearly identical velocity?
A
(Figure 1) is the velocity-versus-time graph for an object moving along the x-axis. During which segment(s) is the object moving to the right (in the positive x-direction)?
A B
(Figure 1) is the velocity-versus-time graph for an object moving along the x-axis. During which segment(s) is the velocity constant?
A D F
The figure shows a position-versus-time graph. (Figure 1) At which lettered point or points is the object slowing down?
A and E
Choose an example of a vertical motion with a negative velocity and a negative acceleration.
A ball dropped from a height during its downward motion.
Choose an example of a vertical motion with a positive velocity and a negative acceleration.
A ball thrown upward, before it starts to fall back down.
Which of the following motions is described by the motion diagram of the figure? (Figure 1)
A car pulling away from a stop sign
Which of the following motions could be described by the motion diagram of the (Figure 1) ?
A cyclist braking to a stop.
The bacterium Escherichia coli (or E. coli), is a single-celled organism that lives in the gut of healthy humans and animals. When grown in a uniform medium rich in salts and amino acids, it swims along zig-zag paths at a constant speed. (Figure 1) shows the positions of an E. coli as it moves from point A to point J. Each segment of the motion can be identified by two letters, such as segment BC. During which segments, if any, does the bacterium have the same displacement?
AB and CD
The bacterium Escherichia coli (or E. coli), is a single-celled organism that lives in the gut of healthy humans and animals. When grown in a uniform medium rich in salts and amino acids, it swims along zig-zag paths at a constant speed. (Figure 1) shows the positions of an E. coli as it moves from point A to point J. Each segment of the motion can be identified by two letters, such as segment BC. During which segments, if any, does the bacterium have the same velocity?
AB and CD
The gas pedal in a car is sometimes referred to as "the accelerator." Which other controls on the vehicle can be used to produce acceleration?
All of the above
The figure is a motion diagram with the clock reading (in seconds) shown at each position. The positions for t≥16 s are offset for clarity, but the motion actually occurs along a single track.(Figure 1)
B
The figure shows a position-versus-time graph. (Figure 1) At which lettered point or points is the object turning around?
B
(Figure 1) is the velocity-versus-time graph for an object moving along the x-axis. During which segment(s) is the object slowing down?
B E
The figure below shows an object's position-versus-time graph. The letters A to E correspond to various segments of the motion in which the graph has constant slope. (Figure 1) In which segment(s) is the object at rest?
B and D
Velocity-versus-time graphs for three racers are shown in the figure. (Figure 1) At t=5.0s, which car has traveled the furthest?
Betty
Velocity-versus-time graphs for three racers are shown in the figure. (Figure 1) Which of the three drag racers had the greatest acceleration at t=0 s?
Betty
Heather and Jerry are standing on a bridge 51 m above a river. Heather throws a rock straight down with a speed of 17 m/s . Jerry, at exactly the same instant of time, throws a rock straight up with the same speed. Ignore air resistance. Which rock has the faster speed as it hits the water?
Both rocks hit water with equal speeds.
(Figure 1) is the velocity-versus-time graph for an object moving along the x-axis. During which segment(s) is the object speeding up?
C
The figure shows a position-versus-time graph. (Figure 1) At which lettered point or points is the object speeding up?
C
The figure shows the position graph of a car traveling on a straight road as a function of time. (Figure 1) At which labeled instant is the speed of the car greatest?
C
Two cars travel on the parallel lanes of a two-lane road. The cars' motions are represented by the position versus time graph shown in the figure. Answer the questions using the times from the graph indicated by letters. At which of the lettered times, if any, does car #2 momentarily stop?
C
The figure shows a position-versus-time graph. (Figure 1) At which lettered point or points is the object moving to the left (in the negative x-direction)?
C, D, E
The figure shows a position-versus-time graph. (Figure 1) At which lettered point or points is the object moving the fastest?
D
Two cars travel on the parallel lanes of a two-lane road. The cars' motions are represented by the position versus time graph shown in the figure. Answer the questions using the times from the graph indicated by letters. At which of the times do the two cars pass each other?
D - when the lines intersect
(Figure 1) is the velocity-versus-time graph for an object moving along the x-axis. During which segment(s) is the object standing still?
F
The following options describe the motion of four cars. Which car has the largest acceleration?
Goes from 0 m/s to 3.8 m/s in 1.0
A Porsche challenges a Honda to a 400 mm race. Because the Porsche's acceleration of 3.4 m/s2m/s2 is larger than the Honda's 3.0 m/s2m/s2, the Honda gets a 110 mm head start - it is only 290 mm from the finish line. Assume, somewhat unrealistically, that both cars can maintain these accelerations the entire distance Who wins the race?
Honda wins
A man's higher initial acceleration means that a man can outrun a horse over a very short race. A simple - but plausible - model for a sprint by a man and a horse uses the following assumptions: The man accelerates at 6.0 m/s2m/s2 for 1.8 ss and then runs at a constant speed. A horse accelerates at a more modest 5.0 m/s2m/s2 but continues accelerating for 4.8 ss and then continues at a constant speed. A man and a horse are competing in a 200 mm race. The man is given a 100 mm head start, so he begins 100 mm from the finish line. Who wins the race?
man
The figure shows the position graph of a car traveling on a straight road. (Figure 1) The velocity at instant 1 is _________ and the velocity at instant 2 is _________.
negative, negative
Suppose two vectors have unequal magnitudes. Can their sum be zero?
no
Two cars travel on the parallel lanes of a two-lane road. The cars' motions are represented by the position versus time graph shown in the figure. Answer the questions using the times from the graph indicated by letters. Are the two cars traveling in the same direction when they pass each other?
no
Shannon decides to check the accuracy of her speedometer. She adjusts her speed to read exactly 70 mphmph on her speedometer and holds this steady, measuring the time between successive mile markers separated by exactly 1.00 mile. If she measures a time of 47 s , is her speedometer accurate? If not, is the speed it shows too high or too low?
no, too low
Two cars travel on the parallel lanes of a two-lane road. The cars' motions are represented by the position versus time graph shown in the figure. Answer the questions using the times from the graph indicated by letters. At which of the lettered times, if any, does car #1 momentarily stop?
none
You throw a rock upward. The rock is moving upward, but it is slowing down. If we define the ground as the origin, the position of the rock is _____ and the velocity of the rock is _____.
positive, positive
A car skids to a halt to avoid hitting an object in the road. Select the correct motion diagram of the car from the time the skid begins until the instant the car stops.
skid begins 0 0 0 0 stops
A Thompson's gazelle can reach a speed of 13m/s in 3.0s . A lion can reach a speed of 9.5m/s in 1.0s . A trout can reach a speed of 2.8m/s in 0.12s . Which animal has the greatest acceleration?
trout
For a projectile, which of the following quantities are constant during the flight: x, y, vx, vy, v, ax, ay?
vx, ax, ay
A tennis player hits a ball 2.0 m above the ground. The ball leaves his racquet with a speed of 20 m/s at an angle 5.0 ∘ above the horizontal. The horizontal distance to the net is 7.0 m, and the net is 1.0 m high. Does the ball clear the net?
yes
(Figure 1) shows the motion diagram for a rider on a Ferris wheel that was turning at a constant speed. The inset to the figure shows how to find the acceleration vector at the rightmost point. Find the rider's acceleration vector at the highest position of the motion diagram in (Figure 3).
Δv =v 4−v 3
(Figure 1) shows the motion diagram for a rider on a Ferris wheel that was turning at a constant speed. The inset to the figure shows how to find the acceleration vector at the rightmost point. Use a similar analysis to find the rider's acceleration vector at the leftmost position of the motion diagram in (Figure 2).
Δv =v 7−v 6
(Figure 1) shows the motion diagram for a rider on a Ferris wheel that was turning at a constant speed. The inset to the figure shows how to find the acceleration vector at the rightmost point. Find the rider's acceleration vector at the lowest position of the motion diagram in (Figure 3).
Δv =v 9−v 8
