Author: Anonymous

What is slowing the cart? (20 points) Students test a cart connected by a light string over a pulley to a hanging mass. The cart moves right along a level track as the hanging mass moves down. They release the system from rest and use a motion sensor to record cart velocity. Acceleration is found from the slope of each velocity–time graph. Their first calculation assumes the track is frictionless and the string and pulley are ideal. They also run a control trial: disconnect the string and hanging mass, push the 0.90 kg cart to the right, and record how it slows down on the same track with the same motion sensor. The other cart mass used in the main trials is 1.40 kg . Use g = 9.80 m/s² . Take right for the cart and down for the hanging mass as positive. Main trials Trial Cart mass (kg) Hanging mass (kg) Acceleration from velocity–time slope (m/s² ) A 0.90 0.240 1.21 B 0.90 0.360 2.03 C 0.90 0.480 2.71 D 1.40 0.240 0.51 E 1.40 0.480 1.70 Selected sensor readings Time since start (s) Trial A velocity (m/s) Coast-down velocity (m/s) 0.00 0.00 2.00 0.50 0.61 1.46 1.00 1.21 0.92 1.50 1.82 0.38 Show your work. Draw free-body diagrams for the connected cart and hanging mass. Include a possible force the students left out of their model. Also draw a force diagram for the cart while it coasts alone. (3 pts) Use the raw velocity readings to calculate the acceleration for Trial A and for the coast-down test. Explain the signs. (2 pts) Starting with Newton’s second law for each mass, develop the frictionless acceleration equation. Use it for Trials A and D and compare both predictions with the recorded values. (3 pts) From the coast-down test, estimate the resistive force on the lighter cart and a value for the kinetic friction coefficient. What must you assume to use that coefficient for the heavier cart? (3 pts) Now include friction in the connected-system equation. Recalculate A and D and compare your results with the table. (3 pts) What do you think the students overlooked? Support your explanation with three numerical observations, at least one from the coast-down test. Give one other possible cause the data cannot completely exclude. (4 pts) Describe one follow-up test that would help separate your explanation from the alternative. State what you would change, what you would keep the same, and what result you would expect. (2 pts) Upload ONE PDF at the end of the exam containing all of your written solutions. Do not upload a separate file for this question.  

True or False? The stigma of mental illnesses can be countered with education, social interactions between members of majority populations and stigmatized populations, and social activism that promotes more inclusive attitudes and behaviors.

Package release (10 points) A coastal monitoring drone is moving horizontally at 16.0 m/s when it drops a package from a height of 80.0 m . At that moment, a rescue marker is 72.0 m ahead of the package. Take right and up as positive. Ignore air resistance and use g = 9.80 m/s² . Show your work. Draw the path at three points: release, roughly halfway down, and just before landing. At each point, draw and label the horizontal and vertical velocity components and the acceleration. Include the target. (2 pts) Find the time in the air and the horizontal distance traveled. Explain why you used vertical motion to find the time. (2 pts) Find both impact velocity components and the impact speed. Explain the sign of the vertical component. (2 pts) Does the package land before or beyond the target? Calculate the difference. Where should it be released to hit the target with the same speed and altitude? (2 pts) Sketch separate graphs of horizontal velocity versus time and vertical velocity versus time. Label both axes, mark release and impact, and explain the shapes of the two graphs. (2 pts) Upload ONE PDF at the end of the exam containing all of your written solutions. Do not upload a separate file for this question.  

True or False? Because young adults have low rates of mortality compared to older adults, suicide accounts for a larger proportion of young adult mortality than older adult mortality.

True or False? If diagnosed in the early stages, macular degeneration can be reversed with medication.

What is slowing the cart? (20 points) Students test a cart connected by a light string over a pulley to a hanging mass. The cart moves right along a level track as the hanging mass moves down. They release the system from rest and use a motion sensor to record cart velocity. Acceleration is found from the slope of each velocity–time graph. Their first calculation assumes the track is frictionless and the string and pulley are ideal. They also run a control trial: disconnect the string and hanging mass, push the 1.00 kg cart to the right, and record how it slows down on the same track with the same motion sensor. The other cart mass used in the main trials is 1.50 kg . Use g = 9.80 m/s² . Take right for the cart and down for the hanging mass as positive. Main trials Trial Cart mass (kg) Hanging mass (kg) Acceleration from velocity–time slope (m/s²) A 1.00 0.200 1.14 B 1.00 0.300 1.81 C 1.00 0.400 2.38 D 1.50 0.200 0.63 E 1.50 0.400 1.60 Selected sensor readings Time since start (s) Trial A velocity (m/s) Coast-down velocity (m/s) 0.00 0.00 1.20 0.50 0.57 0.90 1.00 1.14 0.60 1.50 1.71 0.30 Show your work. Draw free-body diagrams for the connected cart and hanging mass. Include a possible force the students left out of their model. Also draw a force diagram for the cart while it coasts alone. (3 pts) Use the raw velocity readings to calculate the acceleration for Trial A and for the coast-down test. Explain the signs. (2 pts) Starting with Newton’s second law for each mass, develop the frictionless acceleration equation. Use it for Trials A and D and compare both predictions with the recorded values. (3 pts) From the coast-down test, estimate the resistive force on the lighter cart and a value for the kinetic friction coefficient. What must you assume to use that coefficient for the heavier cart? (3 pts) Now include friction in the connected-system equation. Recalculate A and D and compare your results with the table. (3 pts) What do you think the students overlooked? Support your explanation with three numerical observations, at least one from the coast-down test. Give one other possible cause the data cannot completely exclude. (4 pts) Describe one follow-up test that would help separate your explanation from the alternative. State what you would change, what you would keep the same, and what result you would expect. (2 pts) Upload ONE PDF at the end of the exam containing all of your written solutions. Do not upload a separate file for this question.  

Where does conductive hearing loss originate?

The _____ ratio is a ratio comparing the total number of children and older adults in a population to the number of people aged 15–64 years.

True or False? In most of the world, eldercare is provided by spouses, children, and other family members, and institutionalization of older people is uncommon.

Which term describes a health transition characterized by an increase in the percentage of older adults in the population and a decrease in the percentage of children in the population?