1
WB JEE 2008
+1
-0.25

A rocket of mass 100 kg burns 0.1 kg of fuel per sec. If the velocity of exhaust gas is 1 km/sec, then it lifts with an acceleration of

A
1000 ms$$-$$2
B
100 ms$$-$$2
C
10 ms$$-$$2
D
1 ms$$-$$2
2
WB JEE 2008
+1
-0.25

A bullet emerges from a barrel of length 1.2 m with a speed of 640 ms$$-$$1. Assuming constant acceleration, the approximate time that it spends in the barrel after the gun is fired is

A
4 ms
B
40 ms
C
400 $$\mu$$s
D
1 s
3
WB JEE 2023
+1
-0.25 A body of mass 2 kg moves in a horizontal circular path of radius 5 m. At an instant, its speed is 2$$\sqrt5$$ m/s and is increasing at the rate of 3 m/s$$^2$$. The magnitude of force acting on the body at that instant is,

A
6 N
B
8 N
C
14 N
D
10 N
4
WB JEE 2022
+1
-0.25 If a string, suspended from the ceiling is given a downward force F1, its length becomes L1. Its length is L2, if the downward force is F2. What is its actual length?

A
$${{{L_1} + {L_2}} \over 2}$$
B
$$\sqrt {{L_1}{L_2}}$$
C
$${{{F_2}{L_1} + {F_1}{L_2}} \over {{F_2} + {F_1}}}$$
D
$${{{F_2}{L_1} - {F_1}{L_2}} \over {{F_2} - {F_1}}}$$
WB JEE Subjects
Physics
Mechanics
Electricity
Optics
Modern Physics
Chemistry
Physical Chemistry
Inorganic Chemistry
Organic Chemistry
Mathematics
Algebra
Trigonometry
Coordinate Geometry
Calculus
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