STD 11 - Newtons laws of motion PYQs: JEE Mains Physics – Page 3

Showing 101–114 of 114 questions

101. 101. A spring mass system (mass \(m\), spring constant \(\mathrm{k}\) and natural length \(l\) ) rest in equilibrium on a horizontal disc. The free end of the spring is fixed at the centre of the disc. If the disc together with spring mass system, rotates about it's axis with an angular velocity \(\omega,\left(\mathrm{k} > > \mathrm{m} \omega^{2}\right)\) the relative change in the length of the spring is best given by the option 2020 Medium
102. 102. Particle \(A\) of mass \(m _{1}\) moving with velocity \((\sqrt{3} \hat{i}+\hat{j})\, ms ^{-1}\) collides with another particle \(B\) of mass \(m _{2}\) which is at rest initially. Let \(\overrightarrow{ V }_{1}\) and \(\overrightarrow{ V }_{2}\) be the velocities of particles \(A\) and \(B\) after collision respectively. If \(m _{1}=2\, m _{2}\) and after collision \(\overrightarrow{ V }_{1}=(\hat{ i }+\sqrt{3} \hat{ j })\, ms ^{-1},\) the angle between \(\overrightarrow{ V }_{1}\) and \(\overrightarrow{ V }_{2}\) is\(......^o\) 2020 Hard
103. 103. A ball is thrown upward with an initial velocity \(V_0\) from the surface of the earth. The motion of the ball is affected by a drag force equal to \(m\gamma {v^2}\) (where \(m\) is mass of the ball, \(v\) is its Instantneous velocity and \(\gamma \) is a constant). Time taken by the ball to rise to its zenith is 2019 Hard
104. 104. A body of mass \(m_1\) moving with an unknown velocity of \(v_1 \hat i\) undergoes a collinear collision with a body of mass \(m_2\) moving with a velocity \(v_2 \hat i\) . After collision \(m_1\) and \(m_2\) move with velocities of \(v_3 \hat i\) and \(v_4 \hat i\) respectively. If \(m_2 = 0.5\, m_1\) and \(v_3 = 0.5\, v_1\) then \(v_1\) is: 2019 Medium
105. 105. A man (mass \(= 50\, kg\)) and his son (mass \(= 20\, kg\)) are standing on a frictionless surface facing each other. The man pushes his son so that he starts moving at a speed of \(0.70\, ms^{-1}\) with respect to the man. The speed of the man with respect to the surface is ........ \(ms^{-1}\) 2019 Medium
106. 106. A mass of \(10\,kg\) is suspended vertically by a rope from the roof. When a horizontal force is applied on the rope at some point, the rope deviated at an angle of \(45^o\) at the roof point. If the suspended mass is at equilibrium, the magnitude of the force applied is ..........  \(N\) \((g = 10\,ms^{-2})\)  2019 Medium
107. 107. A particle of mass \(m\) is moving in a straight line with momentum \(p\). Starting at time \(t = 0\), a force \(F = kt\) acts in the same direction on the moving particle during time interval \(T\) so that its momentum changes from \(p\) to \(3p\). Here \(k\) is a constant. The value of \(T\) is 2019 Medium
108. 108. The mass of a hydrogen molecule is \(3.32 \times 10^{-27 } \) \(kg\). If \(10^{23}\) hydrogen molecules strike, per second, a fixed wall of area \(2\) \(cm^2\) at an angle of \(45^o \) to the normal, and rebound elastically with a speed of \(10^3\ m/s\), then the pressure on the wall is nearly: 2018 Medium
109. 109. A particle of mass \(m\) is acted upon by a force \(F\) given by the empirical law \(F = \frac{R}{{{t^2}}}\,v(t)\). If this law is to be tested experimentally by observing the motion starting from rest, the best way is to plot  2016 Hard
110. 110. A large number \((n)\) of identical beads, each of mass \(m\) and radius \(r\) are strung on a thin smooth rigid horizontal rod of length \(L\, (L >> r)\) and are at rest at random positions. The rod is mounted between two rigid supports (see figure) . If one of the beads is now given a speed \(v\), the average force experienced by each support after a long time is (assume all collisions are elastic)
     2015 Hard
111. 111. A body of mass \(5\, kg\) under the action of constant force \(\overrightarrow F  = {F_x}\hat i + {F_y}\hat j\) has velocity at \(t\,= 0\, s\) as \(\overrightarrow v  = \left( {6\hat i - 2\hat j\,m/s} \right)\)  and at \(t\, = 10\,s\) as \(\overrightarrow v  = +6\hat j\,m/s\). The force \(\overrightarrow F \) is  2014 Medium
112. 112. Water is flowing at a speed of \(1.5\, ms^{-1}\) through a horizontal tube of cross-sectional area  \(10^{-2}\, m^2\) and you are trying to stop the flow by your palm. Assuming that the water stops immediately after hitting the palm. the minimum force that you must exert should be ......... \(N\) (density of water \(= 10^3\, kgm^{-3}\)) 2014 Medium
113. 113. A uniform sphere of weight \(W\) and radius \(5\, cm\) is being held by a string as shown in the figure. The tension in the string will be
     2013 Hard
114. 114. Two blocks of mass \(M_1 = 20\,kg\) and \(M_2 = 12\,kg\) are connected by a metal rod of mass \(8\,kg.\) The system is pulled vertically up by applying a force of \(480\,N\) as shown. The tension at the mid-point of the rod is ........ \(N\)
     2013 Hard

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