Physics Laws of Motion

A charge Q is distributed over two concentric conducting thin spherical shells of radii r and R (R > r). If the surface charge densities on the two shells are equal, the electric potential at the common centre is:

A block of mass m = 1 kg slides with velocity v = 6 m/s on a frictionless horizontal surface and collides with a uniform vertical rod and sticks to it as shown. The rod is pivoted about O and swings as a result of the collision making angle θ before momentarily coming to rest. If the rod has mass M = 2 kg, and length l = 1 m, the value of θ is approximately: (take g = 10 m/s²)

A particle of mass m with an initial velocity ui collides perfectly elastically with a mass 3m at rest. It moves with a velocity vj after collision, then v is given by

A bead of mass m stays at point P(a,b) on a wire bent in the shape of a parabola y = Cx² and rotating with angular speed ω (see figure). The value of ω is (neglect friction)

A uniform cylinder of mass M and radius R is to be pulled over a step of height a (a < R) by applying a force F at its centre 'O' perpendicular to the plane through the axes of the cylinder on the edge of the step (see figure). The minimum value of F required is:

Two bodies of the same mass are moving with the same speed, but in different directions in a plane. They have a completely inelastic collision and move together thereafter with a final speed which is half of their initial speed. The angle between the initial velocities of the two bodies (in degree) is

An insect is at the bottom of a hemispherical ditch of radius 1 m. It crawls up the ditch but starts slipping after it is at height h from the bottom. If the coefficient of friction between the ground and the insect is 0.75, then h is: (g = 10 ms?²)

A spaceship in space sweeps stationary interplanetary dust. As a result, its mass increases at a rate dm(t)/dt$$ =bv^2(t), where v(t)$$ its instantaneous velocity. The instantaneous acceleration of the satellite is:

Consider a uniform cubical box of side a on a rough floor that is to be moved by applying minimum possible force $F$ at $a$ point $b$ above its centre of mass (see figure). If the coefficient of friction is $\mu =0.4$ , the maximum possible value of $100*\frac{b}{a}$  for box not to topple before moving i

A mass of $10\mathrm{k}\mathrm{g}$ is suspended by a rope of length $4\mathrm{m}$ , from the ceiling. A force $F$ is applied horizontally at the mid-point of the rope such that the top half of the rope makes an angle of ${45}^{?}$ with the vertical. Then $\mathrm{F}$ equals: (Take $\mathrm{g}=10{\mathrm{m}\mathrm{s}}^{-2}$  and the rope to be massless)