Question

A particle moves from one end of the strip to the other end in time $t$ with uniform velocity. The particle then files off vertically making the strip move on the smooth horizontal table. Further distance travelled by the strip in time $T$ is equal to the length of the strip $L$. Then

A. $T > t$
B. $T = t$
C. $T < t$
D. data is insufficient.

Answer 1

A relative velocity is the velocity of an object or observed in the rest frame of another object. It is basically between two objects, one is an object and the second one is the frame of an object.

Complete step by step answer:

In the given question. The particle and the strip have to move in the opposite direction.
Let their relative velocity is given by ${V_r}.$
So, ${V_r} = \dfrac{L}{t}$
Where, $L \to$ length of the strip
$t \to$time (with uniform velocity).
So, the strip continues to move in its previous speed that is less than the relative velocity. And it will also cover the same distance rather slowly. Therefore, travelled trip time is greater than the time (with uniform velocity).
$\therefore T > t$

Note: Relative velocity is calculated by additional or subtraction method.

Relative velocity$= {V_A} - {V_B}$
$= 10 - ( - 20)$
$= 10 + 20 = 30m/s.$

Formulae:
(1) Velocity of object (A) relative to the object (B)$\to {V_{ab}} = {V_a} - {V_b}$
(2) Velocity of object B relative to, object ${V_{ba}} = {V_b} - {V_a}$