A) 2v
B) v
C) v/2
D) v/3
Correct Answer: C
Solution :
[c] Let x be the length of the shadow of the boy, when he is at a distance y from the lamp. From similar triangles, we have \[=\frac{h}{x}=\frac{3h}{x+y}\text{ or }x=y/2.\] \[\text{Thus }\frac{dx}{dy}=\frac{dy/dt}{2}\]You need to login to perform this action.
You will be redirected in
3 sec