Two stones of masses m and 2m are whirled in horizontal circles, the heavier one in a radius $${r \over 2}$$ and the lighter one in radius r. The tangential speed of lighter stone is n times that of the value of heavier stone when they exprience same centripetal forces. The value of n is
A
4
B
1
C
2
D
3
2
AIPMT 2015
MCQ (Single Correct Answer)
+4
-1
A plank with a box on it at one end is gradually raised about the other end. As the angle of inclination with the horizontal reaches 30o, the box starts to slip and slides 4.0 m down the plank in 4.0 s.
The coefficients of static and kinetic friction between the box and the plank will be, respectively
A
0.5 and 0.6
B
0.4 and 0.3
C
0.6 and 0.6
D
0.6 and 0.5
3
AIPMT 2015
MCQ (Single Correct Answer)
+4
-1
Two particles A and B, move with constant velocities $$\overrightarrow {{v_1}} $$ and $$\overrightarrow {{v_2}} $$. At the initial moment their position vectors are $$\overrightarrow {{r_1}} $$ and $$\overrightarrow {{r_2}} $$ respectively. The condition for particles A and B for their collision is
A
$${\overrightarrow r _1} \times {\overrightarrow v _1} = {\overrightarrow r _2} \times {\overrightarrow v _2}$$
B
$${\overrightarrow r _1} - {\overrightarrow r _2} = {\overrightarrow v _1} - {\overrightarrow v _2}$$
C
$${{{{\overrightarrow r }_1} - {{\overrightarrow r }_2}} \over {\left| {{{\overrightarrow r }_1} - {{\overrightarrow r }_2}} \right|}} = {{{{\overrightarrow v }_2} - {{\overrightarrow v }_1}} \over {\left| {{{\overrightarrow v }_2} - {{\overrightarrow v }_1}} \right|}}$$
D
$${\overrightarrow r _1}.{\overrightarrow v _1} = {\overrightarrow r _2}.{\overrightarrow v _2}$$
4
AIPMT 2015
MCQ (Single Correct Answer)
+4
-1
The heart of a man pumps 5 litres of blood through the arteries per minute at a pressure of 150 mm of mercury. If the density of mercury be 13.6 $$ \times $$ 103 kg/m3 and g = 10 m/s2 then the power (in watt) is
