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ADNAN MUHAMMED

Grade 12,

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a motor car is going due north at a speed of 50km/h. it makes a 90 degree left turn without changing the speed. the change in the velocity of the car is about. 80km.h towards west 70kmk/h towards south – west 70km/h towards north west zero

a motor car is going due north at a speed of 50km/h. it makes a 90 degree left turn without changing the speed. the change in the velocity of the car is about.
  1. 80km.h towards west
  2. 70kmk/h towards south – west
  3. 70km/h towards north west
  4. zero

Grade:12th pass

5 Answers

stenly
33 Points
9 years ago
the magnitude remains constant while the direction changes.draw the resultant.the resultant will be along north west..so, the change in vel is 70kmph towards north-west.
Rahul
21 Points
6 years ago
Use vector concept.. The resultant will be obtained by us in northwest direction so by using triangle law of vector addition we get the ans 70km/hr in north west direction
Manisha
13 Points
6 years ago
The above process is correct but the direction should be south west.Using vector formula u can calculate the magnitude and by drawing diagram the direction.
Jitendra
28 Points
5 years ago
answer will be 70.7 km/h towards south-west
consider these velocities on an x-y plane with vectors i and j (+i = East, -i = West, +j = North, -j = South): 

initial velocity = 50j. 

final velocity = -50i. 

change in velocity (Δv) = final velocity – initial velocity = -50i -50j 
 
and  -i direction (west) and -j direction (south), so the total change in velocity will be pointing towards the southwest.

|Δv| = √[(-50)² + (-50)²] 
|Δv| = 70.7 km/h
Kushagra Madhukar
askIITians Faculty 628 Points
3 years ago
Dear student,
Please find the attached solution to your problem below.
 
Consider these velocities on an x-y plane with vectors i and j (+i = East, -i = West, +j = North, -j = South):
initial velocity = 50j.
final velocity = -50i.
change in velocity (Δv) = final velocity – initial velocity = -50i -50j
and  -i direction (west) and -j direction (south), so the total change in velocity will be pointing towards the southwest.
|Δv| = √[(-50)² + (-50)²]
|Δv| = 70.7 km/h
Hence, 70 km/h towards south – west will be the correct option.
 
Thanks and regards,
Kushagra

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