A particle moves in space along the path $z = ax^3 + by^2$ in such a way that $\frac{dx}{dt} = c = \frac{dy}{dt}.$ Where $a, b$ and $c$ are contants. The acceleration of the particle is
$(6ac^2x + 2bc^2 ) \, \widehat k$
$(2ax^2 + 6by^2 ) \, \widehat k$
$(4bc^2x + 3ac^2 )\, \widehat k$
$(bc^2x + 2by) \, \widehat k$
A car starts from rest and accelerates at $5 \,\mathrm{~m} / \mathrm{s}^{2}$. At $t=4 \mathrm{~s}$, a ball is dropped out of a window by a person sitting in the car. What is the velocity and acceleration of the ball at $\mathrm{t}=6\, \mathrm{~s}$ ?
(Take g $\left.=10\, \mathrm{~m} / \mathrm{s}^{2}\right)$
A man on a rectilinearly moving cart, facing the direction of motion, throws a ball straight up with respect to himself
A body throws a ball upwards with velocity $v_0 = 20\, m/s$ . The wind imparts a horizontal acceleration of $4\, m/s^2$ to the ball. The angle $\theta $ from vertical at which the ball must be thrown so that the ball returns to the boy's hand is $(g = 10\, m/s^2)$
A projectile is fired from horizontal ground with speed $v$ and projection angle $\theta$. When the acceleration due to gravity is $g$, the range of the projectile is $d$. If at the highest point in its trajectory, the projectile enters a different region where the effective acceleration due to gravity is $g^{\prime}=\frac{g}{0.81}$, then the new range is $d^{\prime}=n d$. The value of $n$ is. . . . .