Physics Lab Practical

Lab 10: Waves How did you vary the speed of the pulses in the spring?

A harder strike and tightening the coil

Lab 1: Measurement Consider the results of your reflex time measurement. What precision, in fractions of seconds, can you claim for the stopwatch?

A stopwatch has precision to the hundreds place whereas the reflex testing is precise to the tenths place so there is a limit to its precision.

Lab 7: Torque A mass of 1 kg is located at 0 cm end of the meter stick. If the meter stick is suspended at its center, what mass must be placed at the 75 cm mark to balance the stick?

(1)(10)(50)=(25)(10)(x) 500=250x =2 kg from fulcrum

Lab 1: Measurement How do you find the volume of an object?

(4/3)*pi*R^3 **there is a sphere volume program

What is potential energy?

(mass)(gravity)(height)

Lab 6: Work and Energy What formula was used to find the velocity of the car as it left the vertical position of the track?

(width of the bar on the car)/ time

What is energy?

Energy is the capability to do work

Lab 7: Torque After the meter stick was balanced in part B, the system was in equilibrium. Define equilibrium. Since forced were acting on the meter stick, explain why the meter stick was in equilibrium.

Equilibrium is a state of physical balance where opposing forces and torques are balanced. The forces acting on the meter stick cancel each other out.

Lab 4: Newton's Second Law When the suspended mass was decreased (by a factor of one half) and the mass of the cart held constant what happened to the magnitude of the acceleration? Why?

The acceleration went down by a factor of 1/2 because it is directly proportional to force and the force decreased by a factor of 1/2.

Lab 3: Galileo's Inclined Plane Why are there 2 straight diagonal lines? (Hint: What 2 primary actions of the ball is the motion detector recording)

The ball is hitting the ground and bouncing back up

Lab 9: Density How could you determine the density of your body?

You can determine the density of your body by weighing yourself and converting it to grams and then going in a bathtub, finding the water displacement and dividing them

Heat transfer (or flow) between two objects always occurs to the object of _____________ temperature from the object of ____________ temperature

lower; higher

What is kinetic energy?

1/2(mass)(velocity)^2

What is your weight in a free falling elevator?

0 N

Lab 9: Density What is the density of gold? One ounce of water has a volume of 28.3 ml. What is the volume of one ounce of gold in ml?

1(28.3)=M 28.3= M 28.3/19.3= 1.46ml

Lab 10: Waves How did the two pulses produced at opposite ends behave when they met along the spring? Elaborate on the fact that there are two possible conditions. Illustrate this with a diagram for each

1. At opposite ends the wavelengths met and went flat in the middle 2. When you plucked from the same end the wavelength heightened * I can't draw on here so just look at the lab

Lab 1: Measurement An object is estimated to be 2.5 cm long. When measured with a Vernier caliper its true length is determined to be 2.47 cm. What is the percent error of the estimated value?

1.21 %

Lab 8: Gravity The sun has a diameter of approximately 870,000 miles. By how much would its gravity at its surface increase it were to shrink down (while maintaining its mass) to approximately the size of the earth say to 8700 miles. (Since its a gaseous body it really does not have a surface). Show work. Remember gravity is an inverse square force law.

10,000 times more Fg=G(m1m2)/d2 F1d1=f2d2 idk how this is the answer

Convert the following measurement: 4.54 cm to mm

45.4 mm

Convert the following measurement: 4.54 kg to grams

4540 grams

Lab 6: Work and Energy A car traveling 50 mph takes 100 feet to stop. How much distance is required to stop it at 100 mph.

50(2)=100 mph 100(4)=400 ft

What is gravity?

6.67 x 10 ^-11 Nm^2/kg^2

Lab 4: Newton's Second Law Relate the results of your experiment to the statement of Newton's second law.

A=F/m, as the force increased the acceleration increase, and as the mass increased, the acceleration decreased.

State Newton's Second Law

Acceleration = Force/ Mass

What did Aristotle believe (about falling objects)?

Acceleration increased based on the mass of objects

What affect does changing each of these have on the graph? Amplitude: Wavelength: Phase:

Amplitude: makes the troughs larger and peaks larger Wavelength: increases the distance between peak to peak Phase: shifts wavelength left to right

Lab 5: Conservation of Momentum What's the difference between inelastic and elastic collisions? Is momentum conserved in both? If momentum is not conserved in a collision, what can you conclude?

An elastic collision is when two carts collide but they will not stick together, whereas an inelastic collision is when two carts collide and stick together. Momentum is conserved in both instances due to our results unless there is an outside force (impulse)

Lab 7: Torque At what position along the meter stick did this torque act?

Center of gravity

Lab 11: Heat Transfer Give an everyday example of cooling by conduction, by convection, by forced convection.

Conduction: warming your muscles with a heating pad Convection:Boiling water Forced convection: using a fan on a hot day *minus 2 idk why

Lab 11: Heat Transfer Look at graphs containing the cooling data. Which method of cooling worked best?

Convection (long-term) Conduction (short-term)

A motion detector works by sending out an inaudible (i.e., ultrasonic) sound beam and timing the time it takes to travel from a motion detector to an object and back. The representation of this is a plot of distance versus time. Knowing this, which plot is of an object moving away from the motion detector. Explain your answer.

Distance increases with increased time as you walk away from the motion detector

Lab 5: Conservation of Momentum Using the results from the experiment, determine whether or not momentum is conserved in each part of the experiment. Is momentum conserved in both (all) parts? If not, give some possible sources of error.

Given the results, momentum is conserved in each part of the experiment but some sources of error would be that the one cart could be placed in a different position and human error as well as friction.

What was wrong in the Hellboy movie clips? How did you determine how far he (should have fallen)?

Hellboy should have fallen before he did because of gravity. I determined how far he should have fallen by multiplying 1/2 (gravity)(time)^2

Lab 3: Galileo's Inclined Plane What are possible causes for your data in step 8 not exactly falling on a straight line? What are the most likely causes of experimental uncertainty in the measurements that you made?

Human error which causes our timing to be different and not perfect every time.

Lab 5: Conservation of Momentum What is impulse, and where did you see impulse in the experiment?

Impulse is the change in momentum and yes we did see a change in momentum in the inelastic collisions for the before and after and in the elastic collisions because it is at rest.

Lab 4: Newton's Second Law When the suspended mass was increased and the mass of the cart held constant what happened to the magnitude of the acceleration? Why?

It accelerated faster because the force increased and force is proportional to acceleration.

Lab 7: Torque As you slide the mass further down the meter stick, how does the difficulty of the meter stick change?

It becomes more difficult to hold as you slide the mass further down the meter stick.

Lab 7: Torque In part A, why did it become more difficult to rotate the meter stick each time you repositioned the mass?

It got more difficult to rotate because the distance from the force increases which increased torque

Lab 7: Torque Why is it easier to open a door by pushing on the edge of the door nearer the knob than the hinges

It is easier to open a door by pushing the edge of the door because the distance is bigger than from the hinges so you use less force.

Lab 4: Newton's Second Law When the mass of the cart was increased and the suspended mass held constant, what happened to the magnitude of the acceleration? Why?

It lost acceleration because it is inversely proportional to mass

Lab 3: Galileo's Inclined Plane In what way does your answer refute or support Aristotle's ideas on falling bodies.

It refutes Aristotle's ideas because there are many other factors such as friction and our lack of sufficient evidence for the plastic ball that proves acceleration is dependent on mass.

Why did Galileo use an inclined plane if he was originally interested in measuring objects in free-fall?

It was too hard to measure the acceleration of objects in freewill, so he found that the acceleration is similar on an inclined plane just at a slower rate.

What is the difference between mass and weight?

Mass is measured in kg and is just how much something consists of while weight is mass x gravity (10) and is different in different places

Lab 1: Measurement What is the standard unit for length, mass, and time in the MKS metric system?

Meter, Kilogram, Second

Lab 9: Density If you were given a hollow metal sphere, could you calculate the density of the metal by using the methods in this experiment? Why or why not?

No, because all of the methods in the experiment assume that the mass of the material is equally distributed

Lab 3: Galileo's Inclined Plane Does mass affect acceleration? Prove your answer by discussing the accelerations and masses of the basketball and medicine ball (the mass of the medicine ball is at least 3 times larger than the mass of the basketball)

No, because if the mass affected the acceleration then the medicine ball's slopes would be three times as big.

Lab 11: Heat Transfer Was the heat loss in part D only by conduction? Explain.

No, it was conduction and radiation because it radiates heat constantly

Lab 3: Galileo's Inclined Plane Look at the results of the measurements made in step 9. Does the acceleration depend on the mass of the ball? Explain your answer.

No, just because all three of the trials were slower for the plastic ball than the steel ball going the same distance for our data, doesn't mean mass is the reason for that. The steel ball and the plastic ball have different levels of friction which could explain it. Although, our data supports Aristotle, we know mass is not the dependent of acceleration.

Lab 11: Heat Transfer Why didn't you start collecting data as soon as you put the thermistor in the water?

So the device measuring the temperature would have the same temperature when we started as the water.

Lab 3: Galileo's Inclined Plane Which one of your graphs supports Galileo's findings? Be sure and explain why.

The graph that shows distance and time squared supports Galileo's findings because he found that mathematically distance is proportional to the square of the time the ball rolls.

Lab 6: Work and Energy Compare and discuss the potential and kinetic energies found during this experiment?

The kinetic energies were less than the potential energies. You lose energy because of friction and other variables.

Lab 9: Density Compare the two methods used in parts A and C to find the volume of a regularly shaped object. Which method do you believe was more accurate? Why?

The method used in part A is more accurate because using the density table, the calculations of density using Part A method gives a closer density

Lab 9: Density What are the most probable causes for error in your calculation of the density of water?

The most probable causes for error are the varying precision and accuracies when finding mass and volume *minus 2 idk why

Lab 1: Measurement What was the purpose of this experiment?

The purpose of this experiment is to become familiar with methods of measurement and error.

Lab 7: Torque In part D, there was a mass placed on one side of the fulcrum that caused a torque. When the fulcrum was positioned so that the system was in equilibrium, there must have been a second torque to counteract the first. What produced this second torque?

The second torque was produced by the weight of the meter stick

Lab 10: Waves Describe the motion of the tape as transverse pulses traveled through the spring. Compare its motion to that of the direction of the pulse along the spring. What happened to the pulse when it reached the stationary end of the spring?

The tape bounced back and forth vertically along the same direction as the wave. The wave bounced back inversely related and bounces back negatively. **minus two so idk what the answer is

Lab 10: Waves Describe the motion of the tape as longitudinal pulses traveled through the spring. Compare this motion to that of the pulse along the spring. What happened to the pulse when it reached the stationary end of the spring?

The tape moved forward and backwards. The pulse bounced back when it reached the stationary end.

What is inertia?

The tendency of an object to resist a change in motion

Lab 5: Conservation of Momentum Picture two astronauts holding on to one another in space (their initial velocity with respect to each other is zero). If one astronaut pushes the other away what is the total momentum of both astronauts? If one astronaut weighs (on earth) twice as much as the other what can you say about the velocity of the less massive one compared to the other?

The total momentum of both astronauts is 0. If one astronaut weighs twice as much as the other, the velocity of the less massive guy would be larger (double) the other bigger guy.

A motion detector works by sending out an inaudible (i.e., ultrasonic) sound beam and timing the time it takes to travel from a motion detector to an object and back. The representation of this is a plot of distance versus time. Knowing this, which plot is of a stationary object?Explain your answer.

This is stationary because there is no acceleration.

Lab 10: Waves Explain how you can change the pitch of a string on a guitar. What property of the spring do you vary? Does this change the wavelength of the wave on the string? If so, how? (larger or smaller)

To change the pitch, you can change the tune by changing the tension in the string. You increase the velocity when you make the tension increased. The wavelengths is directly proportional so when velocity increases, wavelength increases.

Lab 11: Heat Transfer Why did you wait the same amount of time before collecting data when comparing cooling methods?

To keep the graphs similar and measure the same time period of cooling

Lab 7: Torque Define torque and draw a diagram that illustrates the definition, labeling where the fulcrum is located and where the distances are measured

Torque is the product of force of gravity and the distance from fulcrum

Lab 7: Torque Identify a measurement device we have been using in this laboratory that makes use of torque.

Triple beam balance

Lab 1: Measurement Why are units important when reporting the result of a measurement?

Units are important because they allow for a comparison to a standard which helps to understand the results.

Lab 4: Newton's Second Law If a cart has a weight of 10 N and is pulled by a constant 20 N force, what is the resulting acceleration? Hint: you must distinguish between mass and weight

W=F= 10 N m= 1 A = 20 N/1 = 20 m/s/s

Lab 3: Galileo's Inclined Plane Why do we find the free- fall acceleration from the line with positive slope? (Hint: remember how moving away from and towards the detector affects velocity)

When the ball is moving away from the detector, the graph goes in a positive direction which shows the slope.

Lab 5: Conservation of Momentum When two cars collide in an automobile accident, what type of collision do the cars (typically) experience? Would it be more damaging to the people inside if the cars struck together or bounced apart? why?

When two cars collide in a car accident, it is usually an inelastic collision. It would be more dangerous if it was an elastic collision because once they collide they will spread apart and hit more objects.

Lab 8: Gravity If you took a bathroom scale into an elevator would you weigh more or less when it accelerated up? What about when it accelerated down? Explain your answer.

When you go up an elevator, you weigh more and when you go down an elevator you weigh less. When you go up an elevator you press more force on the support force, while going down you press less force on the support force.

Lab 4: Newton's Second Law From your velocity versus time graphs, can you conclude that the acceleration of the cart was constant in each case? State your reasons.

Yes, in each trial there were instances of a constant acceleration. If the force is due to gravity, so the acceleration will be constant.

Lab 8: Gravity Did your plots look like an inverse square law plot? Why or why not?

Yes, it did because force and distance are inversely squared proportional

Lab 6: Work and Energy a. Which graph shows a linear relationship? b. Which shows a non-linear? c. What does this say about the relationship between stopping distance and velocity? Keep in mind that the origin must be considered.

a. the height vs. average velocity squared b. the average stopping distance vs. average velocity c. they are not directly proportional

Lab 11: Heat Transfer In parts A: a. Which can cooled fastest? b. Which can heated fastest? c. We know that black is a good absorber of heat simply from wearing a black t-shirt in the sunshine, or touching a black car in the summertime. What can we now conclude about its ability to give off, or emit, heat? Discuss this, and consider this question: Are good absorbers good emitters?

a. black b. black c. Yes, good absorbers are also good emitters. Black surfaces actually radiate more power and are good at both emitting and absorbing.

Which of these is not a mechanism of heat transfer? a. insulation b. convection c. conduction d. radiation

a. insulation

What is the definition of the "point at the center of an object's weight distribution, where the force of gravity can be considered to act"?

center of gravity

What is impulse?

change in momentum

When an elevator accelerates downward does your weight increase or decrease

decrease

What is the definition of density? What are the units of density?

density is the measure of the compactness of matter g/cm^3

What was Sir Isaac Newtons contribution to the Scientific Revolution?

he discovered that gravity is universal

What is impulse, and where did you see impulse in last week's momentum experiment?

impulse is the change in momentum. After and before the collisions there was impulse as momentum at the beginning was 0

What is momentum?

inertia in motion

What is an inelastic collision?

one object collides with another and they stick together

Lab 1: Measurement How do you find the area of an object?

pi * radius of the circle squared **there is a circle area program

Lab 6: Work and Energy Discuss some possible sources of errors.

placing the car at a different spot every time, not measuring exact distance.

Lab 2: Motion How do you walk to create a U- Shaped graph?

slowing walk toward and then speeding up very quickly then standing still and then moving away gradually

What two examples of waves or wave phenomena

sound and radio

Lab 2: Motion What do you do to create a horizontal line on a distance/time graph?

stand still

Which two characteristics affect the frequency? For each, answer if it is directly or inversely proportional to frequency.

velocity directly proportional wavelength inversely proportional

Lab 2: Motion How do you walk to create a straight line that slopes up?

walk away at a constant speed

Lab 2: Motion How do you walk to create a straight line that slopes down?

walk toward at constant speed

Lab 2: Motion How do you move so the graph goes up steeply at first, and then continues up gradually?

walking away fast at first and then instantly slowing down

Lab 1: Measurement Complete the following calculations using the explanation of significant figures given below. When multiplying and dividing several quantities, the number of significant figures in the final answer is the same as the number of significant figures in the quantity with the least amount of significant figures that is being multiplied. When adding and subtracting several quantities, the number of decimal places in the result should equal the smallest number of decimal places of any term in the sum. Given: x= 12.24 y= 5400 z=11.572 Determine: x*y*z= x+z=

x*y*z= 7.6 x 10^5 x+z= 23.81

Lab 1: Measurement How do you find percent error?

|True value- Measured value/true value| * 100 **there is a percent error program