What Formulas Do I Need to Ace My Physics Test Tomorrow?

In summary, the conversation discusses three physics problems and the formulas needed to solve them. The first problem involves an ice skater and the coefficient of friction between the ice and skates. The second problem involves a car exiting a circular ramp and finding the radius using the coefficient of static friction. The third problem involves a rotating pail of water and finding the minimum speed at the top of the circle to prevent spilling. The formulas used in these problems are -μk = ax/g, R = V^2/μg, and V = √(Rg).
  • #1
nissanfreak
11
0
I am looking over my study and have a few questions. How would I solve some of these questions?

1) An ice skater moving at 12m/s coasts to a halt in 95m on an ice surface. What is the coefficient of friction between the ice and skates? QUESTION: is the formula to use for this always going to be -mew with little k = a with little x divided by g? Will the answer be -.077?

2) A car exits from the expressway to a circular exit ramp that posts a maximum exit speed of 35mph (15.6 m/s). If the typical coefficient of static friction between tires and pavement is 0.4, what is the radius of the exit ramp? QUESTION: Is this the formula i need to use to solve this R=Vsquared/mew times g ? The answer I got is 62.018m. Am i doing this right?

3) A pail of water is rotated in a vertical circle of radius 1m. What is the minimum speed of the pail at the top of the circle if no water is to spill out?
QUESTION: Is this the right formula Vsquared=RG? The answer I got is 3.03 m/s(squared) Am I on the the right track with this one?

Please help me do good on my test tomorrow. Any and all help would be greatly appreciated :smile:
 
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  • #2
Hard to tell if its right without seeing the work, but these don't take a lot of calculations, so...

1) An ice skater moving at 12m/s coasts to a halt in 95m on an ice surface. What is the coefficient of friction between the ice and skates? [/B] QUESTION: is the formula to use for this always going to be -mew with little k = a with little x divided by g? Will the answer be -.077?
The answer is right. Also I would't say the formula is always going to be that.


A car exits from the expressway to a circular exit ramp that posts a maximum exit speed of 35mph (15.6 m/s). If the typical coefficient of static friction between tires and pavement is 0.4, what is the radius of the exit ramp? [/B] QUESTION: Is this the formula i need to use to solve this R=Vsquared/mew times g ? The answer I got is 62.018m. Am i doing this right?
correct

3) A pail of water is rotated in a vertical circle of radius 1m. What is the minimum speed of the pail at the top of the circle if no water is to spill out?
QUESTION: Is this the right formula Vsquared=RG? The answer I got is 3.03 m/s(squared) Am I on the the right track with this one?
At a glance your answer is the acceleration, but the question is asking for the speed.
 
  • #3
in addition to previous comments:
1) coeff of friction generally given with (+) number. so here μk=+0.077
2) looks good. can you derive the formula which you stated?
3) basic formula is (mV2)/R = mg
so you're right that V2 = Rg
or V = √(Rg) = √(9.8) = 3.13 m/sec
 

Related to What Formulas Do I Need to Ace My Physics Test Tomorrow?

1. How can I study effectively for my physics test tomorrow?

There are several effective study strategies for preparing for a physics test. First, make sure to review all of your notes and class materials. Then, try practicing with sample problems or quizzes to assess your understanding. Additionally, consider creating flashcards or diagrams to help you remember key concepts. It may also be helpful to study with a group or seek help from a tutor if you are struggling with certain topics.

2. What are some common mistakes to avoid during a physics test?

One common mistake to avoid is not reading the question or instructions carefully. Make sure to understand what the question is asking before attempting to answer it. Additionally, be aware of units and make sure to use the correct ones in your calculations. It is also important to show all of your work and steps, as partial credit may be given even if your final answer is incorrect.

3. How can I manage my time effectively during a physics test?

Time management is crucial during a physics test. Start by carefully reading through all of the questions and making a plan for how long you will spend on each one. If you get stuck on a question, move on to the next one and come back to it later. Also, make sure to budget some time at the end to review your answers and make any necessary corrections.

4. Should I focus on memorizing equations for my physics test?

While it is important to know and understand key equations, it is not necessary to memorize every single one for a physics test. Instead, focus on understanding the concepts behind the equations and how to apply them to different problems. This will not only help you on the test, but also in your overall understanding of physics.

5. What are some tips for staying calm and focused during a physics test?

Staying calm and focused during a test can be challenging, but there are some strategies you can use to help. Take deep breaths and try to relax your body and mind. Remind yourself that you have prepared and are capable of doing well. If you feel yourself getting overwhelmed, take a short break and then return to the test. Finally, remember to stay positive and trust in your abilities.

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