KCET · Physics · Motion In One Dimension
In a lift moving up with an acceleration of \(5 \mathrm{~ms}^{-2}\), a ball is dropped from a height of \(1.25 \mathrm{~m}\). The time taken by the ball to reach the floor of the lift is ... (nearly) \(\left(g=10 \mathrm{~ms}^{-2}\right)\)
- A \(0.3 \mathrm{~s}\)
- B \(0.2 \mathrm{~s}\)
- C \(0.16 \mathrm{~s}\)
- D \(0.4 \mathrm{~s}\)
Answer & Solution
Correct Answer
(D) \(0.4 \mathrm{~s}\)
Step-by-step Solution
Detailed explanation
Distance travelled by ball during fall \(=1.25 \mathrm{~m}\)
By using relation \(s=u t+\frac{1}{2} a t^{2}\)
Here, \(u=0, \quad s=1.25 \mathrm{~m}\),
\(a =(g+a)=(10+5)=15 \mathrm{~m} / \mathrm{s}^{2} \)
\(\Rightarrow 1.25 =\frac{1}{2} \times 15 \times t^{2}, \Rightarrow t^{2}=\frac{2 \times 1.25}{15} \)
\(t^{2} =0.16 \quad \Rightarrow t=0.4 \mathrm{~s}\)
By using relation \(s=u t+\frac{1}{2} a t^{2}\)
Here, \(u=0, \quad s=1.25 \mathrm{~m}\),
\(a =(g+a)=(10+5)=15 \mathrm{~m} / \mathrm{s}^{2} \)
\(\Rightarrow 1.25 =\frac{1}{2} \times 15 \times t^{2}, \Rightarrow t^{2}=\frac{2 \times 1.25}{15} \)
\(t^{2} =0.16 \quad \Rightarrow t=0.4 \mathrm{~s}\)
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
- The distance between an object and its image produced by a converging lens is \(0.72 \mathrm{~m}\). The magnification is 2 . What will be the magnification when the object is moved by \(0.04 \mathrm{~m}\) towards the lens?KCET 2013 Hard
- Which of the following statements is incorrect with reference of 'Nuclear force'?KCET 2025 Medium
- The magnetic field at the center of a current carrying loop of radius \( 0.1 \mathrm{~m} \) is \( 5 \sqrt{5} \) times that at
a point along its axis. The distance of this point from the centre of the loop isKCET 2017 Easy - The spectral series of the hydrogen atom that lies in the visible region of the electromagnetic spectrumKCET 2009 Easy
- The ionisation energy of an electron in the ground state of helium atom is \(24.6 \mathrm{eV}\). The energy required to remove both the electron isKCET 2013 Easy
- A metallic sphere of radius R carrying a charge q is kept at certain distance from another metallic sphere of radius \(\mathrm{R} / 4\) carrying a charge Q . What is the electric flux at any point inside the metallic sphere of radius R due to the sphere of radius \(\mathrm{R} / 4\) ?
KCET 2025 Easy
More PYQs from KCET
- ADA deficiency can be cured byKCET 2022 Easy
- If \(\left|\begin{array}{ccc}1+\sin ^{2} \theta & \cos ^{2} \theta & 4 \sin 2 \theta \\ \sin ^{2} \theta & 1+\cos ^{2} \theta & 4 \sin 2 \theta \\ \sin ^{2} \theta & \cos ^{2} \theta & 4 \sin 2 \theta-1\end{array}\right|=0\) and \(0 < \theta < \frac{\pi}{2}\), then \(\cos 4 \theta\) is equal toKCET 2009 Hard
- The maximum value of \(\frac{\log x}{x}\) in \((2, \infty)\) isKCET 2008 Medium
- The IUPAC name of the complex ion formed when gold dissolves in aquaregia isKCET 2014 Medium
- Thyroxine produced in the thyroid gland is an iodinated derivative ofKCET 2023 Medium
- Reduction of ketones cannot be carried outwith which of the following
reagents ?KCET 2017 Easy