1
JEE Main 2022 (Online) 29th July Morning Shift
+4
-1

If the length of a wire is made double and radius is halved of its respective values. Then, the Young's modulus of the material of the wire will :

A
remain same
B
become 8 times its initial value
C
become $$\frac{1}{4}$$ of its initial value
D
become 4 times its initial value
2
JEE Main 2022 (Online) 28th July Evening Shift
+4
-1

A pressure-pump has a horizontal tube of cross sectional area $$10 \mathrm{~cm}^{2}$$ for the outflow of water at a speed of $$20 \mathrm{~m} / \mathrm{s}$$. The force exerted on the vertical wall just in front of the tube which stops water horizontally flowing out of the tube, is :

[given: density of water $$=1000 \mathrm{~kg} / \mathrm{m}^{3}$$]

A
300 N
B
500 N
C
250 N
D
400 N
3
JEE Main 2022 (Online) 28th July Evening Shift
+4
-1

Consider a cylindrical tank of radius $$1 \mathrm{~m}$$ is filled with water. The top surface of water is at $$15 \mathrm{~m}$$ from the bottom of the cylinder. There is a hole on the wall of cylinder at a height of $$5 \mathrm{~m}$$ from the bottom. A force of $$5 \times 10^{5} \mathrm{~N}$$ is applied an the top surface of water using a piston. The speed of ifflux from the hole will be : (given atmospheric pressure $$\mathrm{P}_{\mathrm{A}}=1.01 \times 10^{5} \mathrm{~Pa}$$, density of water $$\rho_{\mathrm{W}}=1000 \mathrm{~kg} / \mathrm{m}^{3}$$ and gravitational acceleration $$\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^{2}$$ )

A
11.6 m/s
B
10.8 m/s
C
17.8 m/s
D
14.4 m/s
4
JEE Main 2022 (Online) 28th July Morning Shift
+4
-1

A balloon has mass of $$10 \mathrm{~g}$$ in air. The air escapes from the balloon at a uniform rate with velocity $$4.5 \mathrm{~cm} / \mathrm{s}$$. If the balloon shrinks in $$5 \mathrm{~s}$$ completely. Then, the average force acting on that balloon will be (in dyne).

A
3
B
9
C
12
D
18
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