A vehicle travels half the distance $l$ with speed $v_1$ and the other half with speed $v_2$, then its average speed is
$(v_1 + v_2)/2$
$(2v_1 + v_2)/(v_1 + v_2)$
$2v_1v_2/(v_1 + v_2)$
$(l(v_1 + v_2))/v_1v_2$
The displacement of a particle is given by $x = (t-2)^2$ where $x$ is in metre and $t$ in second. The distance covered by the particle in first 4 seconds is
4 m
8 m
12 m
16 m
At a metro station, a girl walks up a stationary escalator in time $t_1$. If she remains stationary on the escalator, then the escalator take her up in time $t_2$. The time taken by her to walk up on the moving escalator will be
$(t_1 + t_2 )/2$
$t_1 t_2 / (t_2 - t_1)$
$t_1 t_2 / (t_1 + t_2)$
$t_1 - t_2$
The variation of quantity A with quantity B, plotted in figure. Describes the motion of a particle in a straight line.
Quantity B may represent time
Quantity A is velocity if motion is uniform
Quantity A is displacement if motion is uniform
Quantity A is velocity if motion is uniformly accelerated
A graph of x versus t is shown in figure. Choose correct alternatives given below
The particle was released from rest at t = 0
At B, the acceleration a > 0
Average velocity for the motion between A and D is positive
The speed at D exceeds that at Ε