1
JEE Main 2022 (Online) 28th June Evening Shift
+4
-1 A block of mass 2 kg moving on a horizontal surface with speed of 4 ms$$-$$1 enters a rough surface ranging from x = 0.5 m to x = 1.5 m. The retarding force in this range of rough surface is related to distance by F = $$-$$kx where k = 12 Nm$$-$$1. The speed of the block as it just crosses the rough surface will be :

A
zero
B
1.5 ms$$-$$1
C
2.0 ms$$-$$1
D
2.5 ms$$-$$1
2
JEE Main 2022 (Online) 28th June Evening Shift
+4
-1 A $$\sqrt {34}$$ m long ladder weighing 10 kg leans on a frictionless wall. Its feet rest on the floor 3 m away from the wall as shown in the figure. If Ef and Fw are the reaction forces of the floor and the wall, then ratio of $${F_w}/{F_f}$$ will be :

(Use g = 10 m/s2.) A
$${6 \over {\sqrt {110} }}$$
B
$${3 \over {\sqrt {113} }}$$
C
$${3 \over {\sqrt {109} }}$$
D
$${2 \over {\sqrt {109} }}$$
3
JEE Main 2022 (Online) 28th June Evening Shift
+4
-1 Water falls from a 40 m high dam at the rate of 9 $$\times$$ 104 kg per hour. Fifty percentage of gravitational potential energy can be converted into electrical energy. Using this hydroelectric energy number of 100 W lamps, that can be lit, is :

(Take g = 10 ms$$-$$2)

A
25
B
50
C
100
D
18
4
JEE Main 2022 (Online) 28th June Evening Shift
+4
-1 Two objects of equal masses placed at certain distance from each other attracts each other with a force of F. If one-third mass of one object is transferred to the other object, then the new force will be :

A
$${2 \over 9}$$ F
B
$${16 \over 9}$$ F
C
$${8 \over 9}$$ F
D
F
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