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 · 4 Apr · Shift 2 · Q63
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 · 4 Apr · Shift 2 · Q63

Work Power and Energy question

2025 · 4 Apr · Shift 2 · Q63

JEE MainPhysicsWork Power and EnergyMCQ+4 / −1
A block of mass 25 kg is pulled along a horizontal surface by a force at an angle 45∘45^{\circ}45∘ with the horizontal. The friction coefficient between the block and the surface is 0.25 . The block travels at a uniform velocity. The work done by the applied force during a displacement of 5 m of the block is :
  1. A
    490 J
  2. B
    970 J
  3. C
    735 J
  4. D
    245 J
View written solutionFree

Correct answer: D

  1. Given data
  • Mass of block: m=25 kgm=25\,\text{kg}m=25kg
  • Coefficient of friction: μ=0.25\mu=0.25μ=0.25
  • Force is applied at angle: θ=45∘\theta=45^\circθ=45∘
  • Displacement: s=5 ms=5\,\text{m}s=5m
  • Block moves with uniform velocity ⇒\Rightarrow⇒ net force is zero.
  1. Forces on the block

Let the applied force be FFF.

Its components are:

Fx=Fcos⁡45∘,Fy=Fsin⁡45∘F_x=F\cos45^\circ, \qquad F_y=F\sin45^\circFx​=Fcos45∘,Fy​=Fsin45∘

Since the force is pulling upward at 45∘45^\circ45∘, the normal reaction becomes:

N=mg−Fsin⁡45∘N=mg-F\sin45^\circN=mg−Fsin45∘

Friction is:

f=μN=μ(mg−Fsin⁡45∘)f=\mu N=\mu\left(mg-F\sin45^\circ\right)f=μN=μ(mg−Fsin45∘)

  1. Horizontal force balance

Because velocity is uniform,

Fcos⁡45∘=fF\cos45^\circ=fFcos45∘=f

So,

Fcos⁡45∘=μ(mg−Fsin⁡45∘)F\cos45^\circ=\mu\left(mg-F\sin45^\circ\right)Fcos45∘=μ(mg−Fsin45∘)

Substitute μ=0.25\mu=0.25μ=0.25 and sin⁡45∘=cos⁡45∘=12\sin45^\circ=\cos45^\circ=\frac{1}{\sqrt{2}}sin45∘=cos45∘=2​1​:

F12=0.25(25g−F12)F\frac{1}{\sqrt{2}}=0.25\left(25g-F\frac{1}{\sqrt{2}}\right)F2​1​=0.25(25g−F2​1​)

Using g=9.8 m/s2g=9.8\,\text{m/s}^2g=9.8m/s2,

F12=0.25(245−F12)F\frac{1}{\sqrt{2}}=0.25\left(245-F\frac{1}{\sqrt{2}}\right)F2​1​=0.25(245−F2​1​)

F12=61.25−0.25F12F\frac{1}{\sqrt{2}}=61.25-0.25F\frac{1}{\sqrt{2}}F2​1​=61.25−0.25F2​1​

1.25F12=61.251.25F\frac{1}{\sqrt{2}}=61.251.25F2​1​=61.25

F12=49 NF\frac{1}{\sqrt{2}}=49\,\text{N}F2​1​=49N

Thus,

Fcos⁡45∘=49 NF\cos45^\circ=49\,\text{N}Fcos45∘=49N

  1. Work done by the applied force

The displacement is horizontal, so only the horizontal component of the force does work:

W=(Fcos⁡45∘)sW=(F\cos45^\circ)sW=(Fcos45∘)s

W=49×5=245 JW=49\times 5=245\,\text{J}W=49×5=245J

  1. Correct option

245 J\boxed{245\,\text{J}}245J​

So the correct option is D.

PreviousNext

More from Work Power and Energy

  • An object of mass 1000 g experiences a time dependent force F=(2ti^+3t2j^​)N. The power generated by the force at time t is:2025 · MCQ
  • Which one of the following forces cannot be expressed in terms of potential energy?2025 · MCQ
  • A force F=2i^+bj^​+k^ is applied on a particle and it undergoes a displacement i^−2j^​−k^ What will be the value of b, if work done on the particle is zero.2025 · MCQ
  • A force f=x2yi^+y2j^​ acts on a particle in a plane x+y=10. The work done by this force during a displacement from (0,0) to (4 m,2 m)…2025 · Numerical
  • A ball having kinetic energy KE, is projected at an angle of 60∘ from the horizontal. What will be the kinetic energy of ball at the highest point of its flight?2025 · MCQ
  • A force F=α+βx2 acts on an object in the x -direction. The work done by the force is 5 J when the object is displaced by 1 m . If the constant α=1 N then β will be2025 · MCQ
  • A bead of mass ' m' slides without friction on the wall of a vertical circular hoop of radius 'R' as shown in figure. The bead moves under the combined action of gravity and a massless spring (k) attached to the bottom of the hoop. The… Includes diagram2025 · MCQ
  • Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: In a central force field, the work done is independent of the path chosen. Reason R: Every force encountered in…2025 · MCQ