A mass \(m\) is attached to a thin wire and whirled in a vertical circle. The wire is most likely to break when:

1. inclined at an angle of \(60^{\circ}\) from vertical.
2. the mass is at the highest point.
3. the wire is horizontal.
4. the mass is at the lowest point.

Subtopic:  Gravitational Potential Energy |
 74%
Level 2: 60%+
NEET - 2019
Hints
Links

A force \(F = (20 + 10 y)\) acts on a particle in the \(y\)-direction where \(F\) is in Newton and \(y\) is in metre. The work done by this force to move the particle from \(y =0\) to \(y =1~\text m\) is:
1. \(20~\text{J}\)
2. \(30~\text{J}\)
3. \(5~\text{J}\)
4. \(25~\text{J}\)
Subtopic:  Work Done by Variable Force |
 77%
Level 2: 60%+
NEET - 2019
Hints
Links

When an object is shot from the bottom of a long, smooth inclined plane kept at an angle of \(60^\circ\) with horizontal, it can travel a distance \(x_1\) along the plane. But when the inclination is decreased to \(30^\circ\) and the same object is shot with the same velocity, it can travel \(x_2\) distance. Then \(x_1:x_2\) will be:

1. \(1:2\sqrt{3}\) 2. \(1:\sqrt{2}\)
3. \(\sqrt{2}:1\) 4. \(1:\sqrt{3}\)
Subtopic:  Conservation of Mechanical Energy |
 76%
Level 2: 60%+
NEET - 2019
Hints
Links

advertisementadvertisement

Body \(\mathrm{A}\) of mass \(4m\) moving with speed \(u\) collides with another body \(\mathrm{B}\) of mass \(2m\) at rest. The collision is head-on and elastic in nature. After the collision, the fraction of energy lost by the colliding body \(\mathrm{A}\) is:

1. \(\dfrac{5}{9}\) 2. \(\dfrac{1}{9}\)
3. \(\dfrac{8}{9}\) 4. \(\dfrac{4}{9}\)
Subtopic:  Collisions |
 66%
Level 2: 60%+
NEET - 2019
Hints

An object flying in the air with velocity \((20 \hat{i}+25 \hat{j}-12 \hat{k})\) suddenly breaks into two pieces whose masses are in the ratio of \(1:5.\) The smaller mass flies off with a velocity \((100 \hat{i}+35 \hat{j}+8 \hat{k})\). The velocity of the larger piece will be:
1. \( 4 \hat{i}+23 \hat{j}-16 \hat{k}\)
2. \( -100 \hat{i}-35 \hat{j}-8 \hat{k} \)
3. \( 20 \hat{i}+15 \hat{j}-80 \hat{k} \)
4. \( -20 \hat{i}-15 \hat{j}-80 \hat{k}\)

Subtopic:  Collisions |
 75%
Level 2: 60%+
NEET - 2019
Hints
Links

A particle of mass \(5m\) at rest suddenly breaks on its own into three fragments. Two fragments of mass \(m\) each move along mutually perpendicular directions with speed \(v\) each. The energy released during the process is:

1. \(\dfrac{3}{5}mv^2\) 2. \(\dfrac{5}{3}mv^2\)
3. \(\dfrac{3}{2}mv^2\) 4. \(\dfrac{4}{3}mv^2\)
Subtopic:  Collisions |
 60%
Level 2: 60%+
NEET - 2019
Hints
Links

advertisementadvertisement

An object of mass \(500~\text g\) initially at rest is acted upon by a variable force whose \(x\)-component varies with \(x\) in the manner shown. The velocities of the object at the points \(x=8~\text m\) and \(x=12~\text m\) would have the respective values of nearly:

           

1. \(18~\text {m/s}\)  and \(22.4~\text {m/s}\)  2. \(23~\text {m/s}\)  and \(22.4~\text {m/s}\) 
3. \(23~\text {m/s}\)  and \(20.6~\text {m/s}\)  4. \(18~\text {m/s}\)  and \(20.6~\text {m/s}\) 
Subtopic:  Work Done by Variable Force |
 60%
Level 2: 60%+
NEET - 2019
Hints
Links

Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine. The losses due to frictional forces are 10% of energy. How much power is generated by the turbine?
(g = 10 m/s2)
1. 8.1 kW 
2. 10.2 kW
3. 12.3 kW
4. 7.0 kW

Subtopic:  Power |
 82%
Level 1: 80%+
NEET - 2021
Hints
Links

The energy that will be ideally radiated by a \(100~\text{kW}\) transmitter in \(1~\text{hr}\) is:
1. \(1\times 10^{5}~\text J\) 2. \(36\times 10^{7}~\text J\)
3. \(36\times 10^{4}~\text J\) 4. \(36\times 10^{5}~\text J\)
Subtopic:  Power |
 76%
Level 2: 60%+
NEET - 2022
Hints

advertisementadvertisement

A shell of mass m is at rest initially. It explodes into three fragments having masses in the ratio \(2:2:1\). If the fragments having equal masses fly off along mutually perpendicular directions with speed \(v,\) the speed of the third (lighter) fragment is:
1. \(3 \sqrt{2} v\) 2. \(v\)
3. \(\sqrt{2} v\) 4. \(2 \sqrt{2} v\)
Subtopic:  Collisions |
 72%
Level 2: 60%+
NEET - 2022
Hints