A car travels half the distance with constant velocity of 40 kmph and the remaining half with a constant velocity of 60 kmph. The average velocity of the car in kmph is

A bullet travelling horizontally looses ${\frac{1}{{20}}^{th}}$ of its velocity while piercing a wooden plank. Then the number of such planks required to stop the bullet is

If the velocity $\left( {in\,\,m{s^{ - 1}}} \right)$ of a particle is given by $4\widehat i + 5t\widehat j$, then the magnitude of its acceleration $\left( {in\,\,m{s^{ - 2}}} \right)$ is

A particle moves in the east direction with 15 m/sec for 2 sec then northwards with 5 m/s for 8 sec. Average speed of the particle is

A particle starts from rest and traverses a distance 2x with uniform acceleration, then moves uniformly over a further distance 4x and finally comes to rest after moving a further distance 6x under uniform retardation. Assuming entire motion to be rectilinear motion, the ratio of average speed over the journey to the maximum speed on its way is

A bullet emerges from a barrel of length 1.2 m with a speed of $640\,\,m{s^{ - 1}}$. Assuming constant acceleration the approximate time that its spends in the barrel after the gun is fired is

A body movies with an initial velocity $10\,\,m{s^{ - 1}}$. . If it covers a distance of 20 m in 2S, then acceleration of the body is

A body A moves with uniform acceleration A and Zero initial velocity, Another body B, starts from the same point moves in the same direction with a constant velocity V.

The two bodies meet after a time t. The value of t is

A particle has initial velocity $\left( {2\hat i + 3\hat j} \right)$ and acceleration $\left( {0.3\hat i + 0.2\hat j} \right)$. The magnitude of velocity after 10 seconds will be

A man of mass M stands at one end of a plank of length which is at rest on a frictionless horizontal surface. The man walks to the other end of the plank. If mass of the plank is M/3, the distance that the man moves relative to ground is

A particle has initial velocity $\left( {2\hat i + 3\hat j} \right)$ and acceleration $\left( {0.3\hat i + 0.2\hat j} \right)$. The magnitude of velocity after 10 seconds will be