A system consists of three masses m1, m2 and m3 connected by a string passing over a pulley P. The mass m1 hangs freely and m2 and m3 are on a rough horizontal table (the coefficient of friction = $$\mu $$). The pulley is frictionless and of negligible mass. The downward acceleration of mass m1 is (Assume m1 = m2 = m3 = m)
A
$${{g\left( {1 - g\mu } \right)} \over 9}$$
B
$${{2g\mu } \over 3}$$
C
$${{g\left( {1 - 2\mu } \right)} \over 3}$$
D
$${{g\left( {1 - 2\mu } \right)} \over 2}$$
2
AIPMT 2014
MCQ (Single Correct Answer)
+4
-1
A balloon with mass m is descending down with an acceleration a (where a < g). How much mass should be removed from it so that it starts moving up with an acceleration a ?
A
$${{2ma} \over {g + a}}$$
B
$${{2ma} \over {g - a}}$$
C
$${{ma} \over {g + a}}$$
D
$${{ma} \over {g - a}}$$
3
AIPMT 2014
MCQ (Single Correct Answer)
+4
-1
The force F acting on a particle of mass m is indicated by the force-time graph shown below. The change in momentum of the particle over the time interval from zero to 8 s is :
A
24 N s
B
20 N s
C
12 N s
D
6 N s
4
AIPMT 2014
MCQ (Single Correct Answer)
+4
-1
A projectile is fired from the surface of the earth with a velocity of 5 m s$$-$$1 and angle $$\theta $$
with the horizontal. Another projectile fired from another planet with a velocity of 3 m s$$-$$1 at the same angle follows a trajectory which is identical with the trajectory of the projectile fired from the earth. The value of the acceleration due to gravity on the planet is (in m s$$-$$2) is
(Given g = 9.8 m s$$-$$2)