Lab 3 Newton\'s Laws for Physics Assignemnt PDF

Preview

Summary

Lab 3 Newton's Laws for Physics AssignemntLab 3 Newton's Laws for Physics AssignemntLab 3 Newton's Laws for Physics AssignemntLab 3 Newton's Laws for Physics Assignemnt...

Description

Lab 3 Newton’s Laws

PHY250L

Student Name: Access Code (located on the lid of your lab kit): “Pre-Lab Questions” “Use the free body diagram of the pulley (Figure 5) to answer the Pre-Lab Questions.” 1. “Draw free body diagrams for M₁ and M₂.” “Insert photo of diagram with your name clearly visible in the background:”

2. “Apply Newton’s Second Law to write the equations for M₁ and M₂. You should get two equations with tension in the string, weight for each mass and accelerations for each mass (a₁ and a₂).”

. 3. “Post-Lab Question 2 results in two equations with three unknowns! A third equation is required to solve the system. What is the third equation?”

The third equation is a1 = a2 = a 4. “In the diagram to the right, there is a 5 kg block of ice on a slippery slope positioned 25° from horizontal. What is the acceleration of the block as it slides down the ramp?”

5. “An object is acted upon by a force that can be modeled by F(t) = 5.6 N î + 2.4 N ĵ. The object has a mass of 3.0 kg and starts at rest. Calculate the velocity v(t) as a function of time.” a = F/M = 5.6 N/3kg î + 2.4 N/3kg ĵ = 1.86 m/s2 î + 0.8 m/s2 ĵ

V(t) = V0(t) + at = 0 + (1.86 m/s2 î + 0.8 m/s2 ĵ) t = (1.86 m/s2 î + 0.8 m/s2 ĵ) t

Lab 3 Newton’s Laws

PHY250L

“Experiment 1: Graphing Linear Motion” “Table 1: Motion of Water Observations” “Motion” “a” “b” “c”

“d”

“Observations” Water came up from the back of the pitcher toward me. No movement of water in the pitcher. Water came out from the opposite site of my turn. If I turned left, water came out from the right. If I turned right, water came out from the left. Water came out from the front of the pitcher away from me.

“Table 2: Observations After Flicking Notecard Off of Cup” “Trial” “1” “2” “3” “4” “5”

“Observations” Notecard slid out from under the washer while the washer fell into the cup. The same as trial 1. Notecard went off in the air and the washer fell to the floor. The same as trial 3. Notecard flew off the cup and the washer fell into the cup.

“Post-Lab Questions” 1. “Explain how your observations of the water and washer demonstrate Newton’s law of inertia.” Newton’s law of inertia says that, in the absence of a net force, a body at rest stays at rest and a moving body continues moving in a straight line with constant speed. My observations demonstrated that both the water and the washer either stayed at rest or kept moving in a certain direction until acted upon by another force. 2. Draw a free body diagram of your containers of water from the situation in Part 1 Step 4d. Draw arrows for the force of gravity, the normal force (your hand pushing up on the container), and the stopping force (your hand accelerating the container as you stop). What is the direction of the water’s acceleration?” See attached picture. “Insert photo of diagram with your name clearly visible in the background:”

Lab 3 Newton’s Laws

PHY250L

3. “Can you think of any instances when you are driving or riding in a car that is similar to this experiment? Describe two instances where you feel forces in a car in terms of inertia.” A sudden right turn would throw the passengers to the left side of the car. A sudden stop would push the passengers in the car forward. 4. “You and your friend both perform 3b of Part 1 of this experiment. You walk at 0.5 m/s, but your friend walks at 1.5 m/s. Which container of water will experience a greater net force?” They will have the same magnitude of net force, which is zero.

“Experiment 2: Newton’s Third Law and Force Pairs” “Table 3: Force on Stationary Springs” “Force on Stationary 10 N Spring Scale (N)” 5.5 “Force on Stationary 5N Spring Scale (N)” 5.5 “Table 4: Spring Scale Force Data” “Suspension Set Up” “0.5 kg Mass on 10 N Spring Scale” “0.5 kg Mass with String on 10 N Spring Scale” “0.5 kg mass, string and 5 N Spring Scale on 10 N spring scale” “0.5 kg mass, string and 5 N Spring Scale on 10 N spring scale on Pulley”

“Force (N) on 10 N Spring Scale”

“Force (N) on 5 N Spring Scale”

5 5 5.2

5

5.1

5

“Post-Lab Questions” 1. “How did the magnitude of the forces on both spring scales compare after you moved the 10 N spring scale?” The two forces had about the same magnitude (5N). 2. “How did the magnitude of the forces on both spring scales compare after you move the 5 N spring scale?” The forces on both spring scales were about the same magnitude (approx. 5N). 3. “Use Newton’s Third Law to explain your observations in Questions 1 and 2.”

Lab 3 Newton’s Laws

PHY250L

Newton's third law says that for every action, there is an equal and opposite reaction. My observations seemed to support this law since I got the same readings - 5N, regardless of how the scales were arranged. 4. “Compare the force on the 10 N spring scale when it was directly attached to the 0.5 kg mass and when there was a string between them.” The readings were very close to 5N, as predicted by Newton’s Third law. The minor differences could be due to the weight of the string. 5. “Compare the force on two spring scales in Steps 5 and 6. What can you conclude about the tension in a string?” The readings in two scales were very close. The tension in the string balances the weight it carries. When the second scale is added, the tension is passed on to the other end of the string. As a result, the readings should be roughly the same assuming the string had no substantial weight and the scales were calibrated properly each time. 6. “Olympic spring Usain Bolt set the world record in the 100 meter dash with a time of 9.58 seconds. The physics behind his performance are impressive. Physicists have modeled his position as a function of time to be as follows:”

“where A=110 m/s, B=12.2 m/s, k=0.9 1/s. Using this information, find his acceleration when t = 0 seconds. If his mass was 86 kg at the time of the race, what was his force at t = 0 seconds. What was the force from the ground on Bolt at t = 0 seconds?” His acceleration was 9.89 m/s2. The force was 850.54 N.

“Insert photo of your experimental setup with your name clearly visible in the background:”

“Experiment 3: Newton’s Third Law and Force Pairs” “Table 5: Motion Data” “Mass of 15 Washers (kg)” “Height (m):” 0.71 “Trial” “1” “2” “3”

0.03

“Average of Mass of Washer (kg)” “Procedure 1”

0.002

“Time(s)” 2.61 2.55 2.48

Lab 3 Newton’s Laws

PHY250L 2.49 2.66 2.55 0.22

“4” “5” “Average” “Average Acceleration (m/s²)” “Procedure 2” “Height (m):” 0.71 “Trial” “1” “2” “3” “4” “5” “Average” “Average Acceleration (m/s²)”

“Time(s)” .78 .75 .92 .83 .71 .79 2.23

“Post-Lab Questions” 1. “Draw a free body diagram for M₁ and M₂ in Procedure 2. Draw force arrows for the force due to gravity acting on both masses (Fᵍ₁ and Fᵍ₂) and the force of tension (Fᵀ). Also draw arrows indicating the direction of acceleration, a.” “Insert photo of diagram with your name clearly visible in the background:”

2. “Use Newton’s Second Law to write an equation for each of the free body diagrams you drew in Question 1. Be sure to use the correct signs to agree with your drawings. Solve these four equations for the force of tension (Fᵀ). Your answer should be written in variable form.”

3. “Set the two resulting expressions for the force of tension equal to one another (as long as the string does not stretch, the magnitude of the acceleration in each equation is the same). Replace Fᵍ₁ and Fᵍ₂ with M₁ and M₂, respectively. Solve the resulting equation for a. Then, go back to Questions 2 and solve for the Fᵀ.”

.

Lab 3 Newton’s Laws

PHY250L

4. “Calculate the acceleration for the two sets of data you recorded and compare these values to those obtained by measuring distance and time using percent error. What factors may cause discrepancies between the two values?”

5. “Calculate the tension in the string for the falling washers. From these two values, and the one where the masses were equal, what trend do you observe in the tension in the string as the acceleration increases? Show all calculations.” As acceleration increases, the tension in the string decreases.

6. “Using the theoretical acceleration found in Question 4 for Procedure 1, find the velocity of the block as a function of time by integration.”...