COMEDK · Physics · 6. Work Power Energy
A block of mass 1.5 kg moves along the floor of a hall with a speed of \(5\ ms^{-1}\). It strikes an uncompressed spring and compresses it till the block becomes motionless. If the force constant of the spring is 10000 Nm\(^{-1}\) and the spring is compressed by 5cm, calculate the effective force of kinetic friction.
- A \(16.4\) N
- B \(0\)
- C \(18.7\) N
- D \(125\) N
Answer & Solution
Correct Answer
(D) \(125\) N
Step-by-step Solution
Detailed explanation
Initial kinetic energy of the block is \(K_i = \dfrac{1}{2}mv^2\). Final kinetic energy of the block is \(K_f = 0\). Work done by the spring force is \(W_s = -\dfrac{1}{2}kx^2\). Work done by the kinetic friction is \(W_f = -f_k x\). Using the work-energy theorem,…
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- Rainbow is formed due toCOMEDK 2013 Easy
- Let \(K_1\) be the maximum kinetic energy of photoelectrons emitted by light of wavelength \(\lambda_1\) and \(K_2\) corresponding to wavelength \(\lambda_2\). If \(\lambda_1=2 \lambda_2\), thenCOMEDK 2023 Medium
- A long solenoid X having 400 turns per cm carries a current I . The magnetic field produced at its centre by this solenoid is \(3.14 \times 10^{-2} T\). The magnetic field produced by another solenoid \(Y\) at its centre having 300 turns per cm carries a current \(\dfrac{\mathrm{I}}{3}\). The magnetic field produced by Y at its centre is:COMEDK 2025 Easy
- An electron has a mass of \(9.1 \times 10^{-31} \mathrm{~kg}\). It revolves round the nucleus in a circular orbit of radius \(0.529 \times 10^{-10} \mathrm{~m}\) at a speed of \(2.2 \times 10^6 \mathrm{~ms}^{-1}\). The magnitude of its angular momentum isCOMEDK 2024 Easy
- The equivalent resistance of the circuit between \(A\) and \(B\) is
COMEDK 2014 Medium - A metallic circular loop is placed with its plane perpendicular to a uniform magnetic field of 0.3 T. If the radius of the loop decreases at a constant rate of \(2\ mm\ s^{-1}\), what will be the induced emf in the loop, when the radius of the loop becomes 5 cm.COMEDK 2026 Medium
More PYQs from COMEDK
- Two subatomic particles 1 and 2, with the same kinetic energies have their de- Broglie wavelengths as \(\lambda_1 \& \lambda_2\) and masses as 3 m and 6 m respectively.
Determine the ratio \(\lambda_1: \lambda_2\).COMEDK 2025 Medium - In a nuclear fusion reaction, two nuclei, \(A\) and \(B\) fuse to produce a nucleus \(C\), releasing an amount of energy \(\Delta \mathrm{E}\) in the process. If the mass defects of the three nuclei are \(\Delta M_A, \Delta M_B\) and \(\Delta M_C\) respectively, then which of the following relations is true? ( \(c\) is the speed of light).COMEDK 2025 Medium
- An electric field and magnetic field \(1.8 \times 10^4\ Vm^{-1}\) and \(6 \times 10^{-3}\ T\) respectively are applied simultaneously on an electron beam such that path of the beam remains undeviated, then the speed of the electron will be:COMEDK 2026 Easy
- For a given Linear Programming problem, the objective function is
\(Z=3 x+2 y\)
Subject to constraints are
\(\begin{aligned}
& 4 x+3 y \leq 60 \\
& x \geq 3 \\
& y \leq 2 x \\
& y \geq 0
\end{aligned}\)
P is one of the corner points of the feasible region for the given Linear Programming problem. Then the coordinate of P isCOMEDK 2025 Medium - Two statements, one Assertion (A) and the other Reason (R) are given. Choose the correct option.
Assertion: 2-aminoethanoic acid and p-aminobenzene sulphonic acid can exist as Zwitter ions while p-aminobenzoic acid cannot.
Reason: When the acid group is a relatively strong proton donor and the \(-\mathrm{NH}_2\) group is sufficiently basic it can accept a \(\mathrm{H}^{+}\)ion from the acid group to form the dipolar ion.COMEDK 2025 Medium - \(\text { In a p-n junction, the depletion layer of thickness } 1 \mu \mathrm{m} \text { has } 0.05 \mathrm{~V} \text { potential across it. The electric field in } N C^{-1} \text { is }\)COMEDK 2024 Easy