College Physics help! answers and procedure?

Question

(1) An athlete swims the length of a 50 m pool in 20 s and makes the return trip to the starting position in 22 s. Determine the average velocities in (a) the first half of the swim, (b) the second half of the swim and the (c) round trip.

(i) (a) 2.5 m/s; (b) -2.27 m/s; (c) 0
(ii) (a) -2.5 m/s; (b) 2.27 m/s; 0.09m/s
(iii) (a) 1.5 m/s; (b) 1.37 m/s; (c) 1 m/s

(2) A car is capable of accelerating at a rate of 6m/s/s. How long does it take for the car to go from a speed of 55 mi/hr to 60 mi/hr ?
(i) 0.7 s
(ii) 1.7 s
(iii) 2.75 S
(iv) 3.7 s

(3) A racer starts his car from rest ad accelerates at 10 m/s/s for a distance of 400 m. (a) How long does the race car take to travel this distance? (b)What is the speed of the race car at the end of the run?

(i) (a) 7.51 m/s; (b) 72.3 m/s
(ii) (a) 8.94 m/s; (b) 89.4 m/s
(iii) (a) 9.94 m/s; (b) 98.4 m/s
(iv) non of the above.

(4) A car is traveling from New York to Miami at 25 m/s. Another car is traveling from Miami to New York also at 25 m/s. Are their velocities equal?

(i) Yes.
(ii) No.

(5)The speed of light is 300000000 m/s. Convert this figure into miles per hour.
(i) 3.5 x 10000000 miles /hour
(ii)6.7 x 100000000 miles/hour
(iii) 5.5 x100000000 miles/hour
(iv) None of the above.

(6) Two points in a rectangular coordinate system have coordinates (5, 3) and (-3, 4) where the units are in centimeters. What is the distance between these points?

(i) 6.1 cm
(ii) 7.3 cm
(iii) 5.2 cm
(iv) None of the above.

Answer 1

1. Velocity = distance / time



2. Convert miles per hour to meters per second. Then find the change in velocity and divide by the acceleration.



3. (a) Acceleration = velocity / time. (b) acceleration * time



4. Think about it.



5. OK, so do it.



6. distance = sqrt( (change in x)^2 + (change in y)^2) )



Frankly, this sounds like intro high school physics, not college physics. If you seriously can't figure these out, you don't belong in this class - I suggest you drop it.

Answer 2

1

Answer 3

Generally, colleges offer at least two levels of introductory physics courses. The first level would be an algebra/trigonometry based approach, where you learn about different theories and formulas and more or less just plug numbers into equations. There will be a little bit of algebraic manipulation required, but nothing too tough. It would be a good idea to brush up on trigonometry though. These level courses are usually not intended for students majoring in engineering or the physical sciences. The second level is usually a Calculus-based physics course that is geared more towards engineering and physics majors. Usually these courses will specifically list Calculus I (and maybe Calculus II) as a prerequisite. Otherwise, the course description will probably mention that it is a course in Calculus physics. This will be a very tough course and will require a much deeper understanding of the theories and formulas. Mathematically speaking, there will be some intensive algebraic manipulation and the need for at least some basic Calculus (taking derivatives and integrals of functions). So, any physics course is going to require a good deal of analytical thinking and at least some basic knowledge of algebra. If I were you, I would shoot for the algebra/trigonometry based physics course. I consider myself to be quite strong in math and the two semesters of Calculus physics courses I had to take included some of the toughest math I have done to date.