Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Work Power and Energy question

2025 · 29 Jan · Shift 1 · Q71
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Main
  3. /Physics
  4. /Work Power and Energy
  5. /2025 · 29 Jan · Shift 1 · Q71

Work Power and Energy question

2025 · 29 Jan · Shift 1 · Q71

JEE MainPhysicsWork Power and EnergyNumerical+4 / −1
In a hydraulic lift, the surface area of the input piston is 6 cm2 and that of the output piston is 1500 cm2. If 100 N force is applied to the input piston to raise the output piston by 20 cm, then the work done is ‾\underline{\hspace{2cm}}​ kJ.
Numerical answer
View written solutionFree

Correct answer: 5

  1. Use Pascal’s law to find the output force

In a hydraulic lift,

F1A1=F2A2\frac{F_1}{A_1} = \frac{F_2}{A_2}A1​F1​​=A2​F2​​

Given:

  • Input area: A1=6 cm2A_1 = 6\,\text{cm}^2A1​=6cm2
  • Output area: A2=1500 cm2A_2 = 1500\,\text{cm}^2A2​=1500cm2
  • Input force: F1=100 NF_1 = 100\,\text{N}F1​=100N

So,

F2=F1A2A1=100×15006F_2 = F_1\frac{A_2}{A_1} = 100\times \frac{1500}{6}F2​=F1​A1​A2​​=100×61500​ F2=100×250=25000 NF_2 = 100\times 250 = 25000\,\text{N}F2​=100×250=25000N
  1. Find the work done in raising the output piston

The output piston rises by

s=20 cm=0.2 ms = 20\,\text{cm} = 0.2\,\text{m}s=20cm=0.2m

Work done:

W=F2s=25000×0.2W = F_2 s = 25000 \times 0.2W=F2​s=25000×0.2 W=5000 JW = 5000\,\text{J}W=5000J
  1. Convert to kJ
5000 J=5 kJ5000\,\text{J} = 5\,\text{kJ}5000J=5kJ
  1. Final answer

The work done is

5\boxed{5}5​

kJ.

PreviousNext

More from Work Power and Energy

  • A sand dropper drops sand of mass m(t) on a conveyer belt at a rate proportional to the square root of speed (v) of the belt, i.e., dtdm​∝v​. If P is the power delivered to run the belt at constant speed then which…2025 · MCQ
  • If a rubber ball falls from a height h and rebounds upto the height of h/2. The percentage loss of total energy of the initial system as well as velocity ball before it strikes the ground, respectively, are :2024 · MCQ
  • A body of m kg slides from rest along the curve of vertical circle from point A to B in friction less path. The velocity of the body at B is: (given, R=14 m,g=10 m/s2 and 2​=1.4) Includes diagram2024 · MCQ
  • A body of mass 50 kg is lifted to a height of 20 m from the ground in the two different ways as shown in the figures. The ratio of work done against the gravity in both the respective cases, will be : Includes diagram2024 · MCQ
  • A body is moving unidirectionally under the influence of a constant power source. Its displacement in time t is proportional to :2024 · MCQ
  • A bullet of mass 50 g is fired with a speed 100 m/s on a plywood and emerges with 40 m/s. The percentage loss of kinetic energy is :2024 · MCQ
  • Four particles A,B,C,D of mass 2m​,m,2m,4m, have same momentum, respectively. The particle with maximum kinetic energy is :2024 · MCQ
  • When kinetic energy of a body becomes 36 times of its original value, the percentage increase in the momentum of the body will be :2024 · MCQ