The velocity of a projectile at the initial point A is (2 i + 3 j) m/s. Its velocity (in m/s) at point B is,

• -2 i - 3 j

• -2 i + 3 j

• 2 i - 3 j

• 2 i - 3 j

A  particle of mass m is released from rest and follows a parabolic path is shown. Assuming that the displacement of the mass from the origin is small, which graph correctly depicts the position of the particle as a function of time?

A body is moving with velocity 30 m/s towards east. After 10 s its velocity becomes 40 m/s towards the north. The average acceleration of the body is 

• 7 m/s²

• 

• 5 m/s²

• 5 m/s²

A missile is fired at maximum range with an initial velocity of 20 m/s. If g =10 m/s² the range of the missile is 

• 50 m

• 60 m

• 20 m

• 20 m

Two particles A and B, move with constant velocities v₁ and v₂. At the initial moment, their position vectors are r₁ and r₂ respectively. The condition for particles A and B for their collision is 

• 

• r₁.v₁ = r₂.v₂

• r₁ x v₁ = r₂ x v₂

• r₁ x v₁ = r₂ x v₂

A projectile is fired an angle of 45^o with the horizontal.Elevation angle of the projectile at the highest point as seen from the point of projection is 

• 60^o

• tan^-1(1/2)

• 
• 

A Particle has initial velocity and has acceleration. Its speed after 10s is

• 7 unit

•  unit

• 8.5 unit

• 8.5 unit

A particle moves a distance x in time t according to equation x  = (t +5)^-1. The acceleration of particle is proportional to

• (velocity)^3/2

• (distance)²

• (distance)^-2

• (distance)^-2

119.

Two particles which are initially at rest, move towards each other under the action of their internal attraction. If their speeds are v and 2v at any instant, then the speed of centre of mass of the system will be

• 2v

• 0

• 1.5 v

• 1.5 v

Six vectors and have the magnitudes and directions indicated in the figure. Which of the following statements is true?