Mid Term Exam Review#1

A bee flies at a constant rate of 5 msms until it notices a flower. It then comes to rest in 5 seconds. Find the acceleration of the bee ifa= ΔvΔtΔvΔt.

-1 ms²

A car traveled at a constant velocity of 70 mph from noon to 2:00 pm. At 3:00 pm the velocity of the car was 80 mph; and finally at 4:30 pm the velocity of the car was 40 mph. Calculate the acceleration of the car between 3:00 and 4:30 pm. Responses

-26.67 mihr²

1. Calculate the average speed in meters/minute for the trip represented by the walk graphed here. 2. What is the average velocity of the person taking this walk?

1. 0.5m/min 2. 0m/h

1. According to the data in Graph A, what is the average speed of the moving object? 2. Compare the data in Graphs A and B. How does the speed of the two objects compare at the end of five seconds?

1. 10m/s 2. Both objects move at a constant speed but object A is twice as fast as B.

1. The graph depicts the motion of two objects. Which statement BEST describes the acceleration of the two objects? 2. Find the four second mark on the X-axis of the graph. What comment BEST describes the two objects' motion from 0 to 4 seconds?

1. Acceleration 1 - constant acceleration. Acceleration 2 - varied acceleration. 2. Both have a constant rate of acceleration but Accel 2's rate is about 4X that of Accel 1.

1.Acceleration is a change in velocity. We usually think of acceleration as speeding up but in science it also includes slowing down, stopping, and changing directions, like turning a corner. Acceleration graphs look different from speed graphs. The variable on the X axis is till time but the variable on the Y axis is now velocity so an acceleration graph is charting change in velocity over time. The device we are using today in class is an accelerometer. The water line, marked at the rubber band, represents a slope of 0 and no acceleration. In our lab today, you will walk holding your accelerometer out, away from your body with both hands.Manuel and Sandy were partners. Sandy held the accelerometer in her hands while Manuel watched the water line. Throughout Sandy's walk, the water line remained level. What does that tell the students about Sandy's motion? 2.As the activity continued, Sandy held the accelerometer out in front of her at about chest level and walked at various speeds across the classroom. Manuel made observations and recorded how the water level changed on the accelerometer. Which of these conclusions about Sandy's movements during the activity is NOT true?

1. Sandy's velocity is constant; her speed and direction did not change. 2. At one time during the activity Sandy stopped moving.

A graph here shows the displacement of two walkers over time. Walker 1 is graphed in red while walker 2 is graphed in blue. Which statements are supported by the information in the graph? Select ALL that apply

1. Walker 2 moved faster overall than walker 1 by the end. 2. Both walkers had reached the same distance at fifteen seconds.

A bicycle rider sees a car up ahead, and slows down to avoid a collision. He starts off traveling at 15msms and slows down to 5msms in 7.5 s. Find the acceleration of the bike rider.

1.33 ms²

What is the velocity in meters per second of a runner who runs exactly 110 m toward the beach in 72 seconds.

1.53 m/s toward the beach

Which graph illustrates constant speed?

1.the amount of salt added to the glass of water 2.a metric ruler

Shannon drove her car 140 miles east at a rate of 70 miles per hour. How long did she travel?

2 hours

During which two minute time period is the temperature of the water changing fastest?

2-4 minutes

A car travels 10 miles East in 30 minutes. What is its velocity in miles per hour?

20 miles per hour East

Marcus drove his Honda Prelude for 4 hours at a rate of 55 miles per hour. How far did he travel?

220 miles

The graph shows the acceleration of a racehorse taking off from a starting gate. By how much did the horse's speed increase between 4 seconds and 6 seconds?

27 m/s

Light travels from the sun to the earth, a distance of 144,000,000,000 meters, in 480 seconds. Calculate the approximate velocity of light in the direction it travels toward the earth

300,000,000 ms

Tommy was walking at a rate of 4 mileshourmileshour at noon and at 12:30 pm he was walking at a brisk rate of 6 mileshourmileshour. Two hours later Tommy was walking at a leisurely rate of 2 mileshourmileshour. What was Tommy's acceleration between noon and 12:30 pm?

4 mileshr²

A car starts from rest at a stop light and reaches 20 m/s in 3.5 s. Determine the acceleration of the car.

5.7 ms²

A horse began running due east and covered 25 km in 4.0 hr. What is the average velocity of the horse?

6.25 km/hr due east

Suppose a rollerblade racer finished a 132 meter race in 18 seconds. What is the average speed of the rollerblade racer?

7.33 m/s

Using the graph, calculate the car's acceleration.

7.5 m/s2

Of the following, which change in motion took the greatest amount of time?

A ball falling at 73 m/s and hitting the ground at 9.8 m/s2s2.

Will notices that crickets seem to chirp more frequently at night in June than they do in October. He asks himself, "How do temperature changes affect how often crickets chirp"? If he were to perform an experiment, which of these statements would be the best hypothesis?

Crickets chirp more frequently as temperature increases.

Which graph illustrates constant speed?

D

The factor being changed by the person doing the experiment in a controlled study is called the

D independent variable.

Speed can be calculated using the formula Speed = [[distance/time]]. Speed can be represented in a distance-time graph as well. Review the data in the distance-time graph. What is BEST description of the relationship between distance over time in this set of data?

Distance increases 10 meters every 5 minutes.

Raul and Tyree have open aluminum cans of soda. The can A is left sitting on the table while the other cans B and C are each heated on a hot plate. Can B is heated to a much higher temperature than can C. The students then monitored the cans for expansion. What would be a reasonable hypothesis for this experiment?

Higher temperature causes greater expansion in aluminum cans.

A golf club company has four models of golf clubs. Average strokes saved per 18 holes is a positive indicator of quality. The more strokes saved, the better the golf clubs. The company wishes to mass-market a lot of golf clubs quickly. Which set would be the best choice for this criteria?

Legacy

You're working with a group of classmates to design a mousetrap car. Which step should be completed last?

Modifying the car.

Roger and Natalie travel in similar cars. Roger's car drives the two miles to school in 7.5 minutes. Natalie drives the same distance in the opposite direction but in only 6.5 minutes. What is true of their velocities?

Natalie's velocity is greater in magnitude than Roger's velocity.

Nick is attempting to develop a new plastic for his chemical company. He hypothesizes that mixing chemical A with chemical B will produce a super-strong plastic that is better than any plastic on the market. Nick places chemical A and chemical B in a beaker and does the experiment. To his dismay, the mixture explodes into a huge purple mushroom cloud, leaving behind an oily, foul-smelling liquid. Nick does this 9 more times and gets the same result 9 times. Finally, Nick rejects his hypothesis.Based on the scientific method, what should Nick do next?

Revise his hypothesis and perform a different experiment.

A team of engineers is designing a new anti-collision device for cars. The device is intended to reduce the chance of collisions between cars.Which step would be MOST appropriate after the design is ready? Responses

Testing the device on model cars in laboratory conditions

A car is traveling at a constant velocity of 60 km/h east for 4 hours.Choose the correct statement about the acceleration of the car.

The acceleration of this car is zero

Susie places 3 beakers in the freezer. The first beaker contains water only, the second contains water and salt, and the third contains a water and sugar solution. Susie recorded the temperature and the time at which each mixture froze. Which is the most appropriate hypothesis for her experiment? Responses

The addition of different substances affects the freezing point of water.

A car traveled at a constant velocity of 70 mph from noon to 2:00 pm. At 3:00 pm the velocity of the car was 80 mph; and finally at 4:30 pm the velocity of the car was 40 mph.Which statement accurately describes the acceleration of the car? Responses

The car had a positive acceleration between 2:00 pm and 3:00 pm.

Company A believes that electric cars are the future of the automotive industry. Which of these factors would prohibit Company A from developing this idea further?

The cost to develop the technology would be greater than what could be made in profits.

While running around the track at school, Milt notices that he runs due East on the 100m homestretch and due West on the 100m backstretch. To train for the 800m event, he runs both the 100m homestretch and the 100m backstretch in 12.2 seconds. How do Milt's velocities on the homestretch and backstretch compare?

The homestretch and backstretch have velocities with the same magnitude only.

Corinne uses a model rocket in her physical science class. The rocket begins its trip traveling vertically at 22 msms. It reaches a peak height of 24 meters and then begins its descent. Just before it hits the ground, it reaches a velocity of 22 msms. Which statement is true regarding the rocket's trip?

The rocket's velocity on the trip down is the negative of the upward trip.

Jane starts driving her car down the road at 30 miles per hour. At the same time, the local train starts going down the tracks. The train is going 35 miles per hour, a little bit faster than Jane's car.After two hours, which will cover the greater distance, the train or the car?

The train.

In which situation is the acceleration of the car negative?

The velocity of a car reduced from 50 km/h to 35 km/h over one minute.

What is the benefit of collaborative discussion when trying to develop a hypothesis about a certain situation?

There is a bigger pool of knowledge to pull from to help you create a hypothesis.

Technological advances in transportation have come about in response to the depletion of fossil fuels and other negative aspects of the internal combustion engine. There are many positives to these advancements, but there are also some negatives. Which statement is a negative aspect of these advancements?

These advancements are very expensive and not available to everyone.

When launched, the Hubble Space Telescope carried a mirror with a wrong shape. This led to images that were not sharply focused. Astronauts were sent on a servicing mission to correct the error after three years. The correction was designed by engineers to make the images much sharper than before.Which step did the engineers take next to decide if the correction was successful?

They compared images of the same space objects before and after the correction.

A team of researchers developed a new chemical for use as antifreeze in car engines. The engineers believe that when the chemical is added to water, the water will freeze at a lower temperature. Which step must the researchers take before they can consider the product successful?

They must measure the freezing point of water with the chemical added to it.

When something is moving, it is in motion. Pressing the gas pedal in a car will put the car in motion.Two important properties of motion are speed and direction. Speed is how fast an object is moving.If Tony and Tanya both run at the same speed and in the same direction, and they both run for the same amount of time, what can you say about the distance they travel?

They will run an equal distance.

Tommy was walking at a rate of 4 mileshourmileshour at noon and at 12:30 pm he was walking at a brisk rate of 6 mileshourmileshour. Two hours later Tommy was walking at a leisurely rate of 2 mileshourmileshour. Which statement about Tommy's accleration is true?

Tommy had a positive acceleration between noon and 12:30 pm.

Foresters recently noticed an apparent drop in the squirrel population in a near-by oak-hickory forest. The squirrels eat acorns produced on the oak trees; hawks eat squirrels. The foresters are not sure what is causing the decline in the squirrel population but they are concerned that both the squirrel and hawk populations will disappear. How could they best find an answer to their question?

Use a computer simulation model of the potential forest populations.

A design team has come out with four different plans for building a bridge across a small stream. What is the quickest and most economical way of picking the right plan?

Use computer simulations to build models of the four and try them out that way.

Which car is accelerating?

a car that rounds a curve at a constant speed

Hail stones do a lot of damage when they fall to the Earth and hit homes and cars with great force. They hit with great force because they

accelerate as they fall to Earth.

Why does a raindrop accelerate as it falls to the earth?

because the force of gravity pulls on the drop

Why does a skydiver accelerate as she falls to the earth before opening her chute?

because the force of the earth pulls on her

Consider the average speed of a runner who jogs around a track four times. The distance (400m) remains constant for each lap. However, each lap is run 5 seconds slower than the first. The time for each lap increases. The average speed for each lap ______________. This is an example of a(n) _____________ relationship. Responses

decreases, inverse

Sally and Juan's science teacher challenged her students to build a paper airplane that would stay airborne for ninety seconds. The students have two days to design and test their planes. The assignment will end with a "fly-off". First Sally and Juan researched plane designs. Then Sally and Juan built their first plane. Whenever they tested the plane, it would take a nose dive straight into the floor. They changed the design by reshaping the nose of the plane and adding some weight to the tail. The plane flew, but did not get very far. Finally they tried to change the way they threw the plane. After many tries, their plane stayed in the air an average of ninety-two seconds.Sally and Juan's research and first plane design would be considered which part of the technological design process?

designing a product

Sally and Juan's science teacher challenged her students to build a paper airplane that would stay airborne for ninety seconds. The students have two days to design and test their planes. The assignment will end with a "fly-off". First Sally and Juan researched plane designs. Then Sally and Juan built their first plane. Whenever they tested the plane, it would take a nose dive straight into the floor. They changed the design by reshaping the nose of the plane and adding some weight to the tail. The plane flew, but did not get very far. Finally they tried to change the way they threw the plane. After many tries, their plane stayed in the air an average of ninety-two seconds.What is the next step in the technological design process? Responses

evaluating the design

That was the challenge in science class. Ben and Sam designed a pendulum to move the wood block. Their first design moved the block about 1.5 meters. They rebuilt their pendulum and changed the mass of the pendulum bob. After they made several changes in the mass of the bob, they finally knocked the wooden block 7.0 meters.Each time Ben and Sam tried a new mass for the pendulum bob they were Responses

evaluating the design.

This was the challenge in science class. Ben and Sam designed a pendulum to move the wood block. Their first design moved the block about 1.5 meters. They rebuilt their pendulum and changed the mass of the pendulum bob. After the changes, the boys knocked the block of wood 4 meters, 6 meters, and finally 8 meters. The average distance the block moved after the final changes to the pendulum was 6 meters. The boys won the design challenge.Changing the pendulum design after the first trial was an example of _____________ to solve the problem presented by the teacher.

evaluating the model

Science and technology have developed cleaner fuels such as EA-85 fuel. What is a positive impact that this new fuel may have on society?

fuel with less emissions

You own a high speed digital camera that can take a picture every 0.5 seconds. You decide to take a picture every 0.5 seconds of your physics teacher as she drops a watermelon off the top of the school. After you develop and analyze the pictures, you realize that the distance the watermelon falls from the teacher in each new picture is

gradually more in each picture.

Sally and Juan's science teacher has directed the class to build a paper airplane. The challenge is to build an airplane that flies the farthest distance. The students have two days to design and test their planes. The assignment will end with a "fly-off". Sally and Juan built their first plane. Whenever they tested the plane, it would take a nose dive into the floor. They changed the design by reshaping the nose of the plane and adding some weight to the tail. The plane flew, but did not get very far. Next they tried to change the way they threw the plane. After many tries, their plane flew an average distance of 35 meters.

implementing a design

Three features describe the motion of an object. They are

position, direction, and speed.

A skydiver has reached the point where the force of air resistance equals the force of gravity. Until she opens her parachute, her acceleration will

remain at 0 m/s2.

Which is a standard metric base unit, correctly matched with what it measures?

second: time

The measure of the distance an object travels in a certain length of time is the object's

speed.

Assuming the downward direction to be positive, the acceleration of gravity is about 10 ms2ms2. This means that

the velocity of a falling body increases by 10 msms every second.

The graph shown here MOST LIKELY represents the motion of a train with

thrust equal to its resistance.