Click to Chat

1800-2000-838

+91-120-4616500

CART 0

• 0

MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping
        the resultant vector P AND Q IS R IF Q IS DOUBLED R IS DOUBLED WHEN Q IS REVERSED R IS AGAIN DOUBLED FIND P:Q:R
7 months ago

## Answers : (1)

Arun
12304 Points
							Dear student
p^2 + q^2 + 2pq cos @ = r^2           ...(i)
p^2 + 4q^2 + 4pq cos @ = 4r^2           …...(ii)
p^2 + q^2 – 2pq cos @ = 4r^2        …....(iii)
equation (i) – (iii)
pq cos@ =  –3 r^2 /4
p^2 + q^2 = 5/2 * r^2
p^2 + 4 q^2 = 7 r^2
p^2 + q^2 = 5/2 * r^2
on solving
p^2 = r^2
and
q^2 = 3/2 * r^2
hence
p^2 : q^2: r^2 = 2 : 3: 2
p : q : r  = $\small \sqrt$2 : $\small \sqrt$3 : $\small \sqrt$2
Regards
Arun (askIITians forum expert)

6 months ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies

## Other Related Questions on Discuss with colleagues and IITians

View all Questions »

## COUPON CODE: SELF10

### Course Features

• 728 Video Lectures
• Revision Notes
• Previous Year Papers
• Mind Map
• Study Planner
• NCERT Solutions
• Discussion Forum
• Test paper with Video Solution

### Course Features

• 731 Video Lectures
• Revision Notes
• Test paper with Video Solution
• Mind Map
• Study Planner
• NCERT Solutions
• Discussion Forum
• Previous Year Exam Questions