1Here comes one more problem..
The length of the latus rectum of the parabola which has focus at (- 1, 1) and directrix 4x + 3y - 24 = 0 is
a. 4
b. 6
c. 8
d. 10
1. Two particles are simultaneously projected in horizontal direction with speed of 4m/s and 8m/s respectively in opposite directions from a tower of height 10 m. The displacement vectors of two particles
a. never be perpendicular to each other
b. are perpendicular at √2 s.
c. are perpendicular at (4/5) √2 s
d. are perpendicular at (2/3) √2 s.
2. Suppose a particle of mass m is in circular orbit under an attractive central force, which is inversely proportional to nth power of the distance. Then the square of time period of its revolution is proportional to
a. r ^3n/2
b. r^n+1
c. r^2n-1
d. r^(n+4)/2
3.Three identical solid spheres, each of mass 2 kg, are placed at three corners of an equilateral triangle of side 0.5 m. The work done on the system to double the side of the triangle is (in joules)
a. 2G
B. 6G
C. 12G
D. 4G
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14 Answers
62sunil.. check the question.. you have missed two characters .. after "with speed of"
1Someone reply guys.........
the question r nt toooooooooo tough.....
11@ satyajeet
those are options.
please tell me which one is correct and how?
1I can't exactly tell coz dats how d question is given in the book???
1@satyajeet. pls do xplain how the solution has been reached........
1Q5. In an experiment, an object is kept at a distance of 60 cm in front of a convex mirror. A plane mirror is introduced covering the lower half of the convex mirror. When the plane mirror is kept at a distance of 40 cm from the object, there is no parallax between the images formed by the two mirrors. The focal length of the convex mirror then is
a. 40cm
b. 35cm.
c. 25 cm.
d. 45 cm
1Q6. In how many ways can 5 prizes be given away to 4 boys, given that each boy is eligible for all the prizes?
a. 1
b. 64
c. 256
d. 1024
1well you could wait for the solutions they give.
then you may ask the questions whose solution doesn't seem convincing to you.
needless to say there will be a lot of solution unconvincing.
Aside : i just hope someone from Brilliant tutorials reads this -they seem to have got a new bloke for physics ... and in a bid to raise the standard of the questions they are ending up with either incomplete questions, wrong questions and obviously wrong solutions !
for example in one question they asked the kinetic energy about a point... and for angular momentum he doesn't find it important enough to mention the point about which ang momentum is to be considered. ! ? !
14 d
Distance between the focus and directrix is 5=2a, using the formula for distance frm pt. to line
Length of LR=4a=10, a has its gen meaning
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