JEE Main · 2009 · 12 Apr 2009 · Offline · Kinematics

A projectile is thrown upward at an angle $60^{\circ }$ with the horizontal. The speed of the projectile is 20 m/s when its direction of motion is $45^{\circ }$ with the horizontal. The initial speed of the projectile is ______ m/s.

A river of width 200 m is flowing from west to east with a speed of $18\mathrm{km}/\mathrm{h}$. A boat, moving with speed of $36\mathrm{km}/\mathrm{h}$ in still water, is made to travel one-round trip (bank to bank of the river). Minimum time taken by the boat for thi …

An object is projected with kinetic energy K from a point A at an angle $60^{\circ }$ with the horizontal. The ratio of the difference in kinetic energies points B and C to that at point A (see figure), in the absence of air friction is :

A block is sliding down on an inclined plane of slope $\theta$ and at an instant $t=0$ this block is given an upward momentum so that it starts moving up on the inclined surface with velocity $u$. The distance $(S)$ travelled by the block before its velocity become zero, …

A paratrooper jumps from an aeroplane and opens a parachute after 2 s of free fall and starts deaccelerating with $3\mathrm{m}/{\mathrm{s}}^2$. At 10 m height from ground, while descending with the help of parachute, the speed of paratrooper is …

A bead $P$ sliding on a frictionless semi-circular string $(ACB)$ and it is at point $S$ at $\mathrm{t}=0$ and at this instant the horizontal component of its velocity is $v$. Another bead $Q$ of the same mass as $P$ is ejected from point $A$ at $\mathrm{t}=0$ …