A body is projected with velocity \(20\sqrt3 \text{  m/s}\) with an angle of projection \(60^°\) with the horizontal. The velocity at the point where the body makes an angle \(30^°  \)with the horizontal is:

1. \(20 \text{  m/s}\)

2. \(\dfrac{20}{\sqrt3} \text{  m/s}\)

3. \(10\sqrt3 \text{  m/s}\)

4. \(10 \text{  m/s}\)

In a uniform circular motion, which of the following quantity is not constant

1. Angular momentum

2. Speed

3. Kinetic energy

4. Momentum

A particle projected with kinetic energy ${\mathrm{k}}_0$ with an angle of projection $\mathrm{\theta }$. Then the variation of kinetic K with vertical displacement y is

1.  linear

2.  parabolic

3.  hyperbolic

4.  periodic

A body is projected with a velocity \(u\) with an angle of projection \(\theta.\) The change in velocity after the time \((t)\) from the time of projection will be:

A particle has initial velocity $\left(3\hat{\mathrm{i}}+4\hat{\mathrm{j}}\right)$ and has acceleration $\left(0.4\hat{\mathrm{i}}+0.3\hat{\mathrm{j}}\right)$. Its speed after 10 s:

1. 7 units

2. $7\sqrt{2}$ units

3. 8.5 units

4. 10 units

The gravity in space is given by \(\vec g=-10 \hat j\ \text{m/s}^{2}\). Two particles are simultaneously projected with velocity \(\vec u_1=10\ \text{m/s} \hat i+10\ \text{m/s} \hat j\) and \(\vec u_2=20\ \text{m/s} \hat i+10\ \text{m/s} \hat j\). Then, the ratio of their times of flight is:

1. \(1:1\)

2. \(1:2\)

3. \(2:1\)

4. None of the above

What determines the nature of the path followed by the particle?

1. Speed only

2. Velocity only

3. Acceleration only

4. None of these

A boat is sent across a river in a perpendicular direction with a velocity of \(8\ \text{km/hr}\). If the resultant velocity of the boat is \(10\ \text{km/hr}\), then the velocity of the river is: 

1. \(10\ \text{km/hr}\)

2. \(8\ \text{km/hr}\) 

3. \(6\ \text{km/hr}\) 

4. \(4\ \text{km/hr}\) 

A river is flowing from W to E with a speed of 5 m/min. A man can swim in still water with a velocity 10 m/min. In which direction should the man swim so as to take the shortest possible path to go to the south. 

1. 30° with downstream

2. 60° with downstream

3. 120° with downstream

4. South

A train is moving towards the east and a car is along the north at the same speed. The observed direction of the car to the passenger on the train is: