$A$ projectile is launched at an angle $\alpha$ with the horizontal with a velocity $20 \; m/s$. After $10 \; s$,its inclination with the horizontal is $\beta$. The value of $\tan \beta$ will be: $(g = 10 \; m/s^2)$

Two stones are projected so as to reach the same horizontal range on a horizontal surface. The maximum height reached by one exceeds the other by an amount equal to half the sum of the heights attained by them. Then,the angle of projection of the stone which attains the smaller height is $........$

Two boys conducted experiments on projectile motion with a stopwatch and noted some readings. As one boy throws a stone into the air at an angle with the horizontal,the other boy observes that after $4 \ s$,the stone is moving at an angle of $30^{\circ}$ to the horizontal,and after another $2 \ s$,it is traveling horizontally. The magnitude of the initial velocity of the stone is (Acceleration due to gravity,$g = 10 \ ms^{-2}$):

$A$ particle starts from the origin at $t=0$ with an initial velocity of $3.0 \hat{i} \; m/s$ and moves in the $x-y$ plane with a constant acceleration $(6.0 \hat{i} + 4.0 \hat{j}) \; m/s^2$. The $x$-coordinate of the particle at the instant when its $y$-coordinate is $32 \; m$ is $D$ meters. The value of $D$ is

$A$ body of mass $1\, kg$ tied to one end of a string is revolved in a horizontal circle of radius $0.1\, m$ with a speed of $3$ revolutions per second. Assuming the effect of gravity is negligible,the linear velocity,acceleration,and tension in the string will be:

Two cars $S_1$ and $S_2$ are moving in coplanar concentric circular tracks in the opposite sense with the periods of revolution $3 \, min$ and $24 \, min$,respectively. At time $t = 0$,the cars are farthest apart. Then,the two cars will be