multiple choice (4 Viewers)

[matt_f64]

FINALLY someone puts 1 A. how in the hell is it B the question bloody tells you max height is same yet range is double. THAT INSTNALTY TELLS YOU THAT ONE HAS MORE TIME THAN THE OTHER.

how can they have the same velocity. think about it as half-flight motion, if u drop somethin off a cliff and at the same time u push somethin horizontally off a cliff, both land at the same time.

 

[Shuter]

Yeah sorry people, I typoed on the first one, wasn't thinking. It is B not A.

 

[Rorix]

6 is D

unfortunately


B represents the person going at a constant velocity which is greater than that of the ball

 

[SeDaTeD]

If he was going at a constant velocity faster than the ball, then the answer would be D. If u let the difference in horizontal velocity be V, then x_2dot=0, x_dot = V, x=Vt, y_2dot=-g, y_dot=-gt, y= -1/2 gt^2. x^2 = V^2 t^2, yx^-2 = -g/2V^2 => y = -gx^2 / 2V^2, which is a concave down parabolic path, which is D. It is clearly not C or A, and if you look for my earlier post, I have done similarly to show that it is B.

 

[Shuter]

6 is most definatly B. The easiest way to think about it is let acceleration sideways equal 9.8m/s. Therefore the object will fall in a strait line at 45*. A different constant acceleration just changes the gradient of the line.

 

[Li0n]

ahh apologies, the different angles gave it away.. gah didnt notice.
i just thought that because the angles were different, they obviously gave different ranges.
12/15 for me...

 

[nicola99]

ARGH! I MISREAD 6.

i totally ignored "from the frame of reference of the vehicle"

*bangs head on table*

So did I!!!! sooooo annoyed

 

[BillyMak]

I misread the bit that said it was accelerating, so I chose A which is obviously wrong :S

 

[paztaboy]

does anybody know the answer for 11? has anybody asked their teachers?

 

[BillyMak]

See thread "induction motor or cooktop?"

A lot of debate over this question.