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
Menu
sneha sneha Grade: 12
        

when a man moves down an inclined plane with const. speed 5m/swhich make an angle 37 with the horizontal, he finds rain falling vertically downwards. when he moves up the same inclined plane with same speed , he finds the rain making an tan^-1(7/8)with horizontal then speed of rain is?

7 years ago

Answers : (2)

AJIT AskiitiansExpert-IITD
68 Points
										

Dear sneha ,


 



2095_21440_Untitled.gif


Please see the figure to find the axis assumed.


let the x- component of rain be x and that of y be y . Now , apply the concepts of relative velocity , subtract the x component of man's velocity from rain 's xcomponent and same for y component of rain. 


now , man's x component = 5 *cos37 = 4 m/s , man's y component  = 5 sin37 = - 3 m/s


so , velocity of rain relative to man  : x component  =  x -(4 ) = (x - 4)   m/s ; y component  = (y +3) m/s 


as the velocity seems vertical horizontal component must be zero , so x - 4 =0 ,  x = 4 m/s


second case , man's x component = - 5 *cos37 =  -4 m/s , man's y component  = 5 sin37 = 3 m/s


so , velocity of rain relative to man  : x component  =  x -( -4 ) = (x + 4)   m/s ; y component  = (y -3) m/s


as angle from the horizontal is tan ^-1 (7/8)  , ; 7/8  = -( y- 3) / x +4 


7/8 = 3-y /8 , therefore , y = -4 m/s , i.e 4m/s downwards .


so velocity of rain is (42 +42 )1/2  =  5.65 m/s   45deg to the vertical.


 


GOOD LUCK !!!


 


Please feel free to post as many doubts on our discussion forum as you can. We are all IITians and here to help you in your IIT JEE preparation.


Now you can win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.



7 years ago
Smriti Singh
16 Points
										I have another doubt:This may be a little simple for you... But please help me.. Not able to understand at all... And please give an appropriate hint for any future reference to such or similar type of questions:QUESTION:Rain is falling with a speed of 20 ms–1. A man rides a bicycle holds an umbrella making an angle of 300 with vertical. When he halves his speed, he has to hold the umbrella vertically for maximum protection. The initial speed of bicycle is   (a) 3 5 ms–1 (b) 10 ms–1 (c)  3 10 ms–1 (d) 20 ms–1
										
4 years ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies
  • Complete JEE Main/Advanced Course and Test Series
  • OFFERED PRICE: Rs. 15,900
  • View Details
  • Kinematics & Rotational Motion
  • OFFERED PRICE: Rs. 636
  • View Details

Ask Experts

Have any Question? Ask Experts

Post Question

 
 
Answer ‘n’ Earn
Attractive Gift
Vouchers
To Win!!! Click Here for details