1
AIPMT 2009
MCQ (Single Correct Answer)
+4
-1
If $$\overrightarrow F $$ is the force acting on a particle having position vector $$\overrightarrow r $$ and $$\overrightarrow \tau $$ be the torque of this force about the origin, then
A
$$\overrightarrow r .\overrightarrow \tau > 0$$  and  $$\overrightarrow F .\overrightarrow \tau < 0$$
B
$$\overrightarrow r .\overrightarrow \tau = 0$$  and  $$\overrightarrow F .\overrightarrow \tau = 0$$
C
$$\overrightarrow r .\overrightarrow \tau = 0$$  and  $$\overrightarrow F .\overrightarrow \tau \ne 0$$
D
$$\vec r.\vec \tau \ne 0$$  and  $$\overrightarrow F .\overrightarrow \tau = 0$$
2
AIPMT 2009
MCQ (Single Correct Answer)
+4
-1
A block of mass M is attached to the lower end of a vertical spring. The spring is hung from a ceiling and has force constant value k. The mass is released from rest with the spring initially unstretched. The maximum extension produced in the length of the spring will be
A
2Mg/k
B
4Mg/k
C
Mg/2k
D
Mg/k
3
AIPMT 2009
MCQ (Single Correct Answer)
+4
-1
An engine pumps water continuously through a hose. Water leaves the hose with a velocity v and m is the mass per unit length of the water jet. What is the rate at which kinetic energy is imparted to water?
A
mv3
B
$${1 \over 2}m{v^2}$$
C
$${1 \over 2}{m^2}{v^2}$$
D
$${1 \over 2}m{v^3}$$
4
AIPMT 2009
MCQ (Single Correct Answer)
+4
-1
An explosion blows a rock into three parts. Two parts go off at right angles to each other. These two are, 1 kg first part moving with a velocity of 12 m s$$-$$1 and 2 kg second part moving with a velocity 8 m s$$-$$1. If the third part flies off with a velocity of 4 m s$$-$$1, its mass would be :
A
7 kg
B
17 kg
C
3 kg
D
5 kg