okay, so for 1. I think it's B because A can't be true since part of the slope is negative and thus negative velocity. C can't be true because at t=1 the velocity is positive, and t=7 the velocity is negative. D can't be true because the acceleration is zero at that point because the position plot is a line without a changing slope. E can't be true because at t=6, the ball has a negative velocity.haruspex said:I get different answers for 1, 10, 11, 13, 14, 16.
RUphysics3 said:okay, so for 1. I think it's B because A can't be true since part of the slope is negative and thus negative velocity. C can't be true because at t=1 the velocity is positive, and t=7 the velocity is negative. D can't be true because the acceleration is zero at that point because the position plot is a line without a changing slope. E can't be true because at t=6, the ball has a negative velocity.
Now ,
10. The helicopter goes up 1000 m. Now it begins to move 45 degrees at an acceleration of 2 m/s^2 for 30 seconds.. so final velocity= 2(30). to find avg velocity, i did (vfinal-vinitial)/2 which brings us to 30. so 30 m/s * 30 seconds = 900 ft..so i did 900+1000 = 1900..i think i went wrong somewhere calculating velocity because Vinitial might not have been 0 as the copter was already in motion but idk how to find vinitial..
11. i don't even know how to approach this question. i suppose its something to do with projectile motion definitions.. maybe to do with the the independence of x and y components
13. Now i got D. i got this because i re-read the question, it says "relative to the water", so I just divided .20 km by 8 m/s to see how long it would take.
14. I got D, i just added the components of the two forces and solved for magnitude.
16. now i got B, realized i plugged into equation incorrectly..
All good now except for 13.RUphysics3 said:okay so..
10. found it somewhere online. i was calculating it where it was 1000 feet straight up and then 900 ft in a direction that was 45 degrees clockwise to that, but apparently it's supposed to be a 90 degree turn then 900 feet. so then its just sqrt(1000^2+900^2)=1350 (A)
11. Okay, so h=1/2gt^2. so as max height increases, so does time in air. this means that C must be correct!
Please post a new thread for this.RUphysics3 said:also... this one : http://www.physics.rutgers.edu/ugrad/123/prevExams/P123_F13_CH1.pdf
1. D
2.A
3.A
4.D
5.E
6.C
7.A
8.B
9.C
10.B
11.E
12.B
Having someone double check your answers to a practice exam is extremely important. It allows for any mistakes or misunderstandings to be caught and corrected, which can greatly improve your understanding of the material.
You can ask anyone you trust to double check your answers, such as a classmate, teacher, or tutor. It's important to choose someone who has a good understanding of the material and can provide helpful feedback.
The best way to know if your practice exam answers are correct is to compare them to the correct answers provided by your teacher or the answer key. If you have someone double check your answers, they can also help identify any incorrect or unclear responses.
No, having someone double check your answers is not considered cheating. It is a helpful study strategy that can improve your understanding of the material and prepare you for the actual exam. However, it is important to make sure the person double checking your answers is not giving you the correct answers without allowing you to think for yourself.
It is recommended to have someone double check your practice exam answers at least once, but you can also have multiple people check them for different perspectives. Ultimately, the goal is to identify any mistakes and improve your understanding, so it's up to you to decide how many times you need to have your answers checked.