1
IIT-JEE 2002 Screening
+2
-0.5
An ideal spring with spring-constant k is hung from the ceiling and a block of mass M is attached to its lower end. The mass is released with the spring initially unstretched. Then the maximum extension in the spring is
A
$${{4Mg} \over k}$$
B
$${{2Mg} \over k}$$
C
$${{Mg} \over k}$$
D
$${{Mg} \over {2k}}$$
2
IIT-JEE 2000 Screening
+2
-0.5
A wind-powered generator converts wind energy into electrical energy. Assume that the generator converts a fixed fraction of the wind energy intercepted by its blades into electrical energy. For wind speed v, the electrical power output will be proportional to
A
v
B
v2
C
v3
D
v4
3
IIT-JEE 1999 Screening
+2
-0.5
A spring of force-constant k is cut into two pieces such that one piece is double the length of the other. Then the long piece will have a force-constant of
A
$$\left( {{2 \over 3}} \right)k$$
B
$$\left( {{3 \over 2}} \right)k$$
C
3 k
D
6 k
4
IIT-JEE 1994
+1
-0.25
A particle of mass m is moving in a circular path of constant radius r such that its centripetal acceleration $${a_c}$$ is varying with time t as $${a_c}$$ = k2rt2 where k is a constant. The power delivered to the perticles by the force acting on it is:
A
$$2\pi m{k^2}{r^2}t$$
B
$$m{k^2}{r^2}t$$
C
$${{\left( {m{k^4}{r^2}{t^5}} \right)} \over 3}$$
D
zero
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