A balloon with mass \(m\) is descending down with an acceleration \(a\) (where \(a<g\)). How much mass should be removed from it so that it starts moving up with an acceleration \(a\)?

1. \( \frac{2 m a}{g+a} \) 2. \( \frac{2 m a}{g-a} \)
3. \( \frac{m a}{g+a} \) 4. \( \frac{m a}{g-a}\)

Subtopic:  Application of Laws |
 62%
From NCERT
AIPMT - 2014
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Three blocks with masses \(m\), \(2m\), and \(3m\) are connected by strings as shown in the figure. After an upward force \(F\) is applied on block \(m\), the masses move upward at constant speed \(v\). What is the net force on the block of mass \(2m\)? (\(g\) is the acceleration due to gravity)

           
1. \(2~mg\) 2. \(3~mg\)
3. \(6~mg\) 4. zero
Subtopic:  Application of Laws |
 75%
From NCERT
AIPMT - 2013
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A person holding a rifle (mass of person and rifle together is \(100\) kg) stands on a smooth surface and fires \(10\) shots horizontally, in \(5\) s. Each bullet has a mass of \(10~\mathrm{g}\) with a muzzle velocity of \(800~\mathrm{ms^{-1}}\). The final velocity acquired by the person and the average force exerted on the person are: 
1. \(-0.08 \mathrm{~ms}^{-1} ; 16 \mathrm{~N} \)
2. \(-0.8 \mathrm{~ms}^{-1} ; 16 \mathrm{~N} \)
3. \(-1.6 \mathrm{~ms}^{-1} ; 16 \mathrm{~N} \)
4. \(-1.6 \mathrm{~ms}^{-1} ; 8 \mathrm{~N}\)
Subtopic:  Application of Laws |
 58%
From NCERT
NEET - 2013
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A person of mass \(60\) kg is inside a lift of mass \(940\) kg and presses the button on control panel. The lift starts moving upwards with an acceleration of \(1.0~\mathrm{ms^{-1}}\). If \(g=10~\mathrm{ms^{-2}}\), the tension in the supporting cable is:
1. \(9680~\mathrm{N}\)
2. \(11000~\mathrm{N}\)
3. \(1200~\mathrm{N}\)
4. \(8600~\mathrm{N}\)

Subtopic:  Application of Laws |
 93%
From NCERT
AIPMT - 2011
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The mass of a lift is \(2000\) kg. When the tension in the supporting cable is \(28000\) N, then its acceleration is:
(Take \(g=10\) m/s2)

1. \(30\) ms-2 downwards 2. \(4\) ms-2 upwards
3. \(4\) ms-2 downwards 4. \(14\) ms-2 upwards
Subtopic:  Application of Laws |
 84%
From NCERT
AIPMT - 2009
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A 0.5 kg ball moving with a speed of 12 m/s strikes a hard wall at an angle of 30° with the wall. It is reflected with the same speed and at the same angle. If the ball is in contact with the wall for 0.25 s, the average force acting on the wall is:
              

1. 48 N

2. 24 N

3. 12 N

4. 96 N

Subtopic:  Application of Laws |
 76%
From NCERT
AIPMT - 2006
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