Question 95: Motion in 2D & Vectors

Question

When a car is at rest, its driver sees rain drops falling on it vertically. When driving the car with
speed v, he sees that rain drops are coming at an angle 60° from the horizontal. On further
increasing the speed of the car to (1 + $$\beta $$)v, this angle changes to 45o. The value of $$\beta $$ is close to :

Accepted Answer

tan 60
o
= $${{{V_r}} \over V}$$ .....(1)
tan 45
o
= $${{{V_r}} \over {\left( {1 + \beta } \right)V}}$$ .....(2)
From (i) and (ii), we get
$${{\sqrt 3 } \over 1} = {{{1 \over V}} \over {{1 \over {\left( {1 + \beta } \right)V}}}}$$
$$ \Rightarrow $$ $${\sqrt 3  = \left( {1 + \beta } \right)}$$
$$ \Rightarrow $$ $$\beta $$ = 0.732

Answer

0.50

Answer

0.73

Answer

0.37

Answer

0.41

Motion in 2D & Vectors

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