What is the value of linear velocity if $\overrightarrow r = 3\widehat i + 4\widehat j + 6\widehat k$ and $\overrightarrow \omega = -5\widehat i + 3\widehat j + 5\widehat k$ ?
$ - 2\widehat i + 45\widehat j - 29\widehat k$
$ 2\widehat i - 45\widehat j + 29\widehat k$
$3\widehat i - 29\widehat j + 45\widehat k$
$5\widehat i - 6\widehat j + 4\widehat k$
A student skates up a ramp that makes an angle $30^{\circ}$ with the horizontal. $He /$ she starts (as shown in the figure) at the bottom of the ramp with speed $v_0$ and wants to turn around over a semicircular path xyz of radius $R$ during which he/she reaches a maximum height $h$ (at point y) from the ground as shown in the figure. Assume that the energy loss is negligible and the force required for this turn at the highest point is provided by his/her weight only. Then ( $g$ is the acceleration due to gravity)
$(A)$ $v_0^2-2 g h=\frac{1}{2} g R$
$(B)$ $v_0^2-2 g h=\frac{\sqrt{3}}{2} g R$
$(C)$ the centripetal force required at points $x$ and $z$ is zero
$(D)$ the centripetal force required is maximum at points $x$ and $z$
A particle moves in a circular path of radius $r$ with speed $v.$ It then increases its speed to $2\,v$ while travelling along the same circular path. The centripetal acceleration of the particle has changed by a factor of
If the length of the second's hand in a stop clock is $3 \,cm$ the angular velocity and linear velocity of the tip is
The acceleration vector of a particle in uniform circular motion averaged over the cycle is a null vector. This statement is