Physic Final

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.

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

Negative position, positive velocity

Determine the sign (positive or negative) of the position and the velocity for the motion diagram in (Figure 3)?

Positive position, negative velocity

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 16 mimi west of the origin, which is defined as the intersection with Mulberry Road. If the car's displacement was -27 mimi , what side of Mulberry Road did the car start on? How far from the intersection was the car at the start?

The car started 11 mimi 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

The bacterium Escherichia 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-μm�m-long cylinder with a 1 μm�m diameter, and it has a mass of 1×10−121×10−12 gg. 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�m/s though not always in the same direction. Answer the following questions about E. coli using SI units (unless specifically requested otherwise) and correct significant figures

What is its diameter? 1*10^-6m

The bacterium Escherichia 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-μm�m-long cylinder with a 1 μm�m diameter, and it has a mass of 1×10−121×10−12 gg. 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�m/s though not always in the same direction. Answer the following questions about E. coli using SI units (unless specifically requested otherwise) and correct significant figures.

What is its length? 2 *10 ^-6 M

The bacterium Escherichia 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-μm�m-long cylinder with a 1 μm�m diameter, and it has a mass of 1×10−121×10−12 gg. 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�m/s though not always in the same direction. Answer the following questions about E. coli using SI units (unless specifically requested otherwise) and correct significant figures

What is its mass? 1*10^-15kg

The bacterium Escherichia 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-μm�m-long cylinder with a 1 μm�m diameter, and it has a mass of 1×10−121×10−12 gg. 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�m/s though not always in the same direction. Answer the following questions about E. coli using SI units (unless specifically requested otherwise) and correct significant figures

What is the length of its DNA, in millimeters? 1mm

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.

What is the tree's speed in m/sm/s? 9×10^−8m/s

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.

What is the tree's speed of growth, in feet per year, from t=1yr�=1yr to t=3yr�=3yr? 9ft/yr

A Thompson's gazelle can reach a speed of 13 m/sm/s in 3.0 ss . A lion can reach a speed of 9.5 m/sm/s in 1.0 ss . A trout can reach a speed of 2.8 m/sm/s in 0.12 ss .

Which animal has the greatest acceleration? trout

At which of the lettered times are the cars moving with nearly identical velocity?

a

During which segments, if any, does the bacterium have the same speed?

all paths

At which of the lettered times, if any, does car #2 momentarily stop?

c

We set the origin of a coordinate system so that the position of a train is x� = 0 mm at t� = 0 ss. (Figure 1) shows the train's velocity graph.

choose the correct position graph for the train

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 speed

A student at the top of a building of height hℎ throws ball A� straight upward with speed v0v0 and throws ball B� straight downward with the same initial speed. Compare the final speeds of the balls as they reach the ground.

equal

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�=��2, 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/sm/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*m^2/s^2

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 equation F=Gm1m2r2�=��1�2�2, where F� is the magnitude of the gravitational attraction on either body, m1�1 and m2�2 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/s2kg⋅m/s2, the units of mass are kgkg, and the units of distance are mm. For this equation to have consistent units, the units of G� must be which of the following?

m3/kg⋅s2

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 kmkm in a time of 5.0 minmin.

1.0m/s

A rectangle has length 3.24 mm and height 0.432 mm . To the correct number of significant figures, what is its area?

1.40m^2

The earth formed 4.57×1094.57×109 years ago. What is this time in seconds?

1.44*10^17s

Estimate the average speed, in m/sm/s, with which the hair on your head grows. Make this estimate from your own experience noting, for instance, how often you cut your hair and how much you trim.

10−8m/s

A person walks briskly at 2.10 m/sm/s . How much time will it take them to walk one mile?

12.8min

A student walks 1.6 mimi west and then 1.6 mimi north. Part complete Afterward, how far is she from her starting point?

2.3mi

A bird flies 3.6 kmkm due west and then 2.1 kmkm due north. Another bird flies 2.1 kmkm due west and 3.6 kmkm due north. What is the angle between the net displacement vectors for the two birds? 29 ∘∘30 ∘∘60 ∘∘90 ∘∘ SubmitPrevious Answers Correct Provide FeedbackNext

29

Compute 3.24 mm + 0.432 mm to the correct number of significant figures.

3.67m

A bird flies 3.8 kmkm due west and then 2.4 kmkm due north. Part complete What is the magnitude of the bird's displacement?

4.5km

Estimate how much time in msms (10−3s10−3s) it will take for a signal to get from your brain to your hand.

40ms

During the summer, when your lawn is growing quickly, estimate this speed, in m/sm/s. Make this estimate from your experience noting, for instance, how often you mow the lawn and what length you trim.

4×10−8m/s

An object's average density ρ� is defined as the ratio of its mass to its volume: ρ=M/V�=�/�. The earth's mass is 5.94×1024kg5.94×1024kg, and its volume is 1.08×1012km31.08×1012km3. What is the earth's average density?

5.50*10^3kg/m^3

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 garden has a circular path of radius 50 mm . John starts at the easternmost point on this path, then walks counterclockwise around the path until he is at its southernmost point. What is the magnitude of John's displacement?

71m

Which of the following motions is described by the motion diagram of the figure?

A car pulling away from a stop sign

Which of the following motions could be described by the motion diagram of the

A cyclist braking to a stop.

During which segments, if any, does the bacterium have the same velocity?

AB and CD

We set the origin of a coordinate system so that the position of a train is x� = 0 mm at t� = 0 ss. (Figure 1) shows the train's velocity graph.

Choose the correct acceleration graph for the train.

At which of the times do the two cars pass each other?

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 displacement? AB and CD

We set the origin of a coordinate system so that the position of a train is x� = 0 mm at t� = 0 ss. (Figure 1) shows the train's velocity graph.

Find the acceleration of the train at t� = 3.0 ss. ax�� = 1.0 ms2ms2

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 not, is the speed it shows too high or too low? too loww

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 ss , is her speedometer accurate?no

The bacterium Escherichia 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-μm�m-long cylinder with a 1 μm�m diameter, and it has a mass of 1×10−121×10−12 gg. 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�m/s though not always in the same direction. Answer the following questions about E. coli using SI 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? 2m

diagram b

negative

diagram c

negative

Are the two cars traveling in the same direction when they pass each other? yesno

no

At which of the lettered times, if any, does car #1 momentarily stop?

none

Diagram (a).

positive

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 garden has a circular path of radius 50 mm . John starts at the easternmost point on this path, then walks counterclockwise around the path until he is at its southernmost point. What is the direction of John's displacement?

southwest

A student at the top of a building of height hℎ throws ball A� straight upward with speed v0v0 and throws ball B� straight downward with the same initial speed. Part complete 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?

they are equal

During which trial or trials is the magnitude of the average velocity the largest?

trial b and trial d