1
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
$${{{F_2}{L_1} - {F_1}{L_2}} \over {{F_2} - {F_1}}}$$
2
WB JEE 2022
+2
-0.5

A golf ball of mass 50 gm placed on a tee, is struck by a golf-club. The speed of the golf ball as it leaves the tee is 100 m/s, the time of contact on the ball is 0.02 s. If the force decreases to zero linearly with time, then the force at the beginning of the contact is

A
100 N
B
200 N
C
250 N
D
500 N
3
WB JEE 2021
+1
-0.25

Three blocks are pushed with a force F across a frictionless table as shown in figure above. Let N1 be the contact force between the left two blocks and N2 be the contact force between the right two blocks. Then,
A
F > N1 > N2
B
F > N2 > N1
C
F > N1 = N2
D
F = N1 = N2
4
WB JEE 2020
+1
-0.25
A block of mass m rests on a horizontal table with a coefficient of static friction $$\mu$$. What minimum force must be applied on the block to drag it on the table?
A
$${\mu \over {\sqrt {1 + {\mu ^2}} }}$$ mg
B
$${{\mu - 1} \over {\mu + 1}}$$ mg
C
$${\mu \over {\sqrt {1 - {\mu ^2}} }}$$ mg
D
$$\mu$$ mg
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Medical
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