A helicopter moving vertically upwards releases a packet when it is at a certain height above the ground. The packet initially moves upwards for a time \(t_1\) and then falls downwards for a time \(t_2\) until it reaches the ground. Then:
1. \(t_1<t_2\)
2. \(t_1=t_2\)
3. \(t_1>t_2\)
4. Data insufficient

A ball is thrown vertically downwards with a velocity of \(20\) m/s from the top of a tower. It hits the ground after some time with the velocity of \(80\) m/s . The height of the tower is: (assuming \(g = 10~\text{m/s}^2)\)$$

If a particle has negative velocity and negative acceleration, its speed:

Suppose you are riding a bike with a speed of \(20\) m/s due east relative to a person \(A\) who is walking on the ground towards the east. If your friend \(B\) walking on the ground due west measures your speed as \(30\) m/s due east, find the relative velocity between two reference frames \(A\) and \(B\):

A particle is moving along the \(x\)-axis such that its velocity varies with time as per the equation \(v = 20\left(1-\frac{t}{2}\right)\). At \(t=0\) particle is at the origin. From the following, select the correct position \((x)\) - time \((t)\) plot for the particle:

1.		2.
3.		4.

Starting from rest, a car accelerates uniformly at the rate of \(1~\text{m/s}^2\) for some time, then decelerates uniformly at the rate of \(2~\text{m/s}^2\) and finally comes to rest after a journey of \(1\) minute. The maximum possible speed of the car during this journey is:
1. \(10\) m/s
2. \(20\) m/s
3. \(30\) m/s
4. \(40\) m/s

The velocity \(v\) of an object varies with its position \(x\) on a straight line as \(v=3\sqrt{x}.\) Its acceleration versus time \((a\text-t)\) graph is best represented by:

1.		2.
3.		4.

Two stones are thrown vertically up simultaneously with different velocities. Which of the following graphs represents the relative separation \((\Delta y)\) between them as a function of time \((t)\)?

1.		2.
3.		4.

A particle starts from rest (with constant acceleration) and acquires velocity \(20\) m/s in \(5\) s. The distance travelled by the particle in the next \(2\) s will be:

The graph below shows position as a function of time for two trains running on parallel tracks.

    
Which of the following statements is true?