JEE Mains · Physics · STD 11 - 3.2 motion in plane
A projectile fired at \(30^{\circ}\) to the ground is observed to be at same height at time \(3 s\) and \(5 s\) after projection, during its flight. The speed of projection of the projectile is \(.........\,ms ^{-1}\)(Given \(g=10\,m s ^{-2}\) )
- A \(70\)
- B \(80\)
- C \(60\)
- D \(50\)
Answer & Solution
Correct Answer
(B) \(80\)
Step-by-step Solution
Detailed explanation
Time of flight \(t_1+t_2=3+5=8\,sec\) \(T =\frac{2 u \sin 30^{\circ}}{ g }\) \(8=\frac{2 u \sin \left(30^{\circ}\right)}{10}\) \(u =80\,m / s\)
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 initial mass of a rocket is \(1000\, {kg} .\) Calculate at what rate the fuel (In \({kg} {s}^{-1}\)) should be burnt so that the rocket is given an acceleration of \(20 \,{ms}^{-2}\). The gases come out at a relative speed of \(500\, {ms}^{-1}\) with respect to the rocket : [Use \( g = 10\, {m} / {s}^{2}\) ]JEE Mains 2021 Medium
- A uniform sphere of mass \(500\; g\) rolls without slipping on a plane horizontal surface with its centre moving at a speed of \(5.00\; \mathrm{cm} / \mathrm{s}\). Its kinetic energy isJEE Mains 2020 Medium
- An inductor of reactance \(100 \Omega\), a capacitor of reactance \(50 \Omega\), and a resistor of resistance \(50 \Omega\) are connected in series with an AC source of 10 V , 50 Hz. Average power dissipated by the circuit is ________ W.JEE Mains 2025 Easy
- The equivalent resistance between \(A\) and \(B\) is \(......\)
JEE Mains 2023 Medium - The de-Broglie wavelength associated with the electron in the \(n\, = 4\) level isJEE Mains 2015 Medium
- The mass of the moon is \(1 / 144\) times the mass of a planet and its diameter \(1 / 16\) times the diameter of a planet. If the escape velocity on the planet is \(\mathrm{v}\), the escape velocity on the moon will be _______.JEE Mains 2024 Hard
More PYQs from JEE Mains
- A particle \(P\) is formed due to a completely inelastic collision of particles \(x\) and \(y\) having de -Broglie wavelengths \({\lambda _x}\) and \({\lambda _y}\) respectively. If \(x\) and \(y\) were moving in opposite directions, then the de -Broglie wavelength of \(P\) isJEE Mains 2019 Medium
- Let \(A=\left(\begin{array}{cc}4 & -2 \\ \alpha & \beta\end{array}\right)\) . If \(A ^{2}+\gamma A +18 I = O\), then \(\operatorname{det}( A )\) is equal toJEE Mains 2022 Easy
- Let \(a_1 , a_2, a_3, .... , a_n\), be in \(A.P\). If \(a_3 + a_7 + a_{11} + a_{15} = 72\) , then the sum of its first \(17\) terms is equal toJEE Mains 2016 Hard
- An object of mass 8 kg is hanging from one end of a uniform rod \(C D\) of mass 2 kg and length 1 m pivoted at its end \(C\) on a vertical wall as shown in figure. It is supported by a cable \(A B\) such that the system is in equilibrium. The tension in the cable is:
(Take \(g=10 m s ^{-2}\) )
JEE Mains 2023 Medium - A natural number has prime factorization given by \(n =2^{ x } 3^{ y } 5^{ z },\) where \(y\) and \(z\) are such that \(y+z=5\) and \(y^{-1}+z^{-1}=\frac{5}{6}, y > z\). Then the number of odd divisors of \(n\), including \(1,\) is ..... .JEE Mains 2021 Hard
- A force on an object of mass \(100\, g\) is \((10 \hat{i}+5 \hat{j}) N\). The position of that object at \(t=\) \(2 s\) is \((a \hat{i}+b \hat{j}) m\) after starting from rest. The value of \(\frac{a}{b}\) will be..........JEE Mains 2022 Medium