A balloon has 2 g of air. A small hole is pierced into it. The air comes out with a velocity of 4 m/s. If the balloon shrinks completely in 2.5 s, the average force acting on the balloon is:

1. 0.008 N

2. 0.0032 N

3. 8 N

4. 3.2 N

In a cricket match, the fielder draws his hands backward after receiving the ball in order to take a catch because:

1. His hands will be saved from getting hurt.

2. He deceives the player.

3. It is a fashion.

4. He catches the ball firmly.

A body is placed on a rough inclined plane of inclination $\mathrm{\theta }$. As the angle $\mathrm{\theta }$ is increased from 0^o to 90^o , the contact force between the block and the plane

1. Remains constant

2. First remains constant then decreases

3. First decreases then increases

4. First increases then decreases

Internal forces can change:

1. the linear momentum but not the kinetic energy of the system.

2. the kinetic energy but not the linear momentum of the system.

3. linear momentum as well as kinetic energy of the system.

4. neither the linear momentum nor the kinetic energy of the system.

A string tied on a roof bears a maximum tension of \(50\) kg-wt. The minimum acceleration that can be acquired by a man of \(98\) kg to descend will be:
[Take \(g=9.8\) m/s²]
1. \(9.8\) m/s²
2. \(4.9\) m/s²
3. \(4.8\) m/s²
4. \(5\) m/s²

A particle of mass 200 g, is whirled into a vertical circle of radius 80 cm using a massless string. The speed of the particle when the string makes an angle of $60°$ with the vertical line is 1.5 ms^-1. The tension in the string at this position is

1. 1 N

2. 1.56 N

3. 2 N

4. 3 N

A particle of mass 200 g is moving in a circle of radius 2 m. The particle is just 'looping the loop'. The speed of the particle and the tension in the string at highest point of the circular path are (g=10 ms^-2)

1. 4 ms^-1, 5 N

2. 4.47 ms^-1, zero

3. 2.47 ms^-1, zero

4. 1 ms^-1, zero

A trolley of mass 200 kg moves with a uniform speed of 36 km/h on a frictionless track. A child of mass 20 kg runs on the trolley from one end to the other (10 m away) with a speed of $4 {\mathrm{ms}}^{-1}$ relative to the trolley in a direction opposite to its motion, and jumps out of the trolley. What is the final speed of the trolley?

1. 1.01 m/s
2. 10.36 m/s
3. 9.64 m/s
4. 11.20 m/s

A 70 kg man stands in contact against the inner wall of a hollow cylindrical drum of radius 3 m rotating about its vertical axis with 200 revs/min. The coefficient of friction between the wall and his clothing is 0.15. What is the minimum rotational speed of the cylinder to enable the man to remain stuck to the wall (without falling) when the floor is suddenly removed?

1. 3.14 rad/s
2. 4.17 rad/s
3. 4.71 rad/s
4. 3.21 rad/s

What is the minimum speed required at the uppermost position to perform a vertical loop if the radius of the chamber is \(25\) m?
1. \(16.7\) m/s
2. \(15.8\) m/s
3. \(35\) m/s
4. \(24\) m/s