WBJEE · Physics · Laws of Motion
A boy of mass \(40 \mathrm{~kg}\) is climbing a vertical pole at a constant speed. If the coefficient of friction between his palms and the pole is 0.8 and \(g=10 \mathrm{~m} / \mathrm{s}^2\), the horizontal force that he is applying on the pole is
- A \(300 \mathrm{~N}\)
- B \(400 \mathrm{~N}\)
- C \(500 \mathrm{~N}\)
- D \(600 \mathrm{~N}\)
Answer & Solution
Correct Answer
(C) \(500 \mathrm{~N}\)
Step-by-step Solution
Detailed explanation
Hints: Here \(\mu=0.8\) Frictional force \(=\mu \mathrm{N}_1=m g\) \[ \mathrm{N}_1=\frac{m g}{\mu}=\frac{400}{0.8}=500 \mathrm{~N} \]
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
- Current through \(\mathrm{ABC}\) and \(\mathrm{A}^{\prime} \mathrm{B}^{\prime} \mathrm{C}^{\prime}\) is \(\mathrm{I}\). What is the magnetic field at \(\mathrm{P}\) ? \(\mathrm{BP}=\mathrm{PB}^{\prime}=\mathrm{r}\left(\right.\) Here \(\mathrm{C}^{\prime} \mathrm{B}^{\prime} \mathrm{PBC}\) are collinear)
WBJEE 2011 Medium - What is the phase difference between two simple harmonic motions represented by \(x_{1}=A \sin \left(\omega t+\frac{\pi}{6}\right)\) and \(x_{2}=A \cos (\omega t) ?\)WBJEE 2012 Easy
- A stream of electrons and protons are directed towards a narrow slit in a screen (see figure). The intervening region has a uniform electric field (vertically downwards) and a uniform magnetic field \(\mathbf{B}\) (out of the plane of the figure) as shown. Then
WBJEE 2014 Easy - What current will flow through the \(2 \mathrm{k} \Omega\) resistor in the circuit shown in the figure?
WBJEE 2012 Medium - If \(\mathrm{R}\) is the Rydberg Constant in \(\mathrm{cm}^{-1}\), then hydrogen atom does not emit any radiation of wave-length in the range ofWBJEE 2020 Medium
- For a domestic AC supply of 220 V at 50 cycles per sec, the potential difference between the terminals of a two-pin electric outlet in a room is given byWBJEE 2025 Easy
More PYQs from WBJEE
- If the total number of m-element subsets of the set \(\mathrm{A}=\left\{\mathrm{a}{1}, \mathrm{a}{2}, \ldots . \mathrm{a}{\mathrm{n}}\right\}\) is \(\mathrm{k}\) times the number of \(\mathrm{m}\) element subsets containing \(\mathrm{a}{4}\), then \(\mathrm{n}\) isWBJEE 2020 Medium
- The speed distribution for a sample of \(N\) gas particles is shown below. \(P(v)=0\) for \(v\gt2 v_0\). How many particles have speeds between \(1.2 \mathrm{v}_0\) and \(1.8 \mathrm{v}_0\) ?
WBJEE 2024 Easy - Let \(S_{n}=\cot ^{-1} 2+\cot ^{-1} 8+\cot ^{-1} 18+\cot ^{-1} 32+\ldots \ldots .\) to \(n^{\text {th }}\) term. Then \(\lim _{n \rightarrow \infty} S_{n}\) isWBJEE 2021 Easy
- The differential of \(f(x)=\log _{e}\left(1+e^{10 x}\right)-\tan ^{-1}\left(e^{5 x}\right)\) at \(x=0\) and for \(d x=0.2\) isWBJEE 2021 Medium
- A smooth massless string passes over a smooth fixed pulley. Two masses \(m_{1}\) and \(m_{2},\left(m_{1}>m_{2}\right)\) are tied at the two ends of the string. The masses are allowed to move under gravity starting from rest. The total external force acting on the two masses isWBJEE 2014 Easy
- The vertex of the parabola \(y^2+6 x-2 y+13=0\) is
\(\begin{aligned}
& (y-1)^2=-6 x-12 \\
& (y-1)^2=-6(x+2)=4\left(\frac{-6}{4}\right)(x+2) \\
& \text { Vertex } \rightarrow(-2,1)
\end{aligned}\)WBJEE 2011 Easy