Kinematics

1

An object moving with a speed of 6.25 m/s, is decelerated at a rate given by dν/dt = 2.5√ν, where ν is the instantaneous speed. The time taken by the object, to come to rest, would be

  1. 8 s
  2. 4 s
  3. 2 s
  4. 1 s
2

A particle is moving with velocity v = K(yi + xj), where K is a constant. The general equation for its path is

  1. xy = constant
  2. y2 = x + constant
  3. y2 = x2 + constant
  4. y = x2 + constant
3

A water fountain on the ground sprinkles water all around it. If the speed of water coming out of the fountain is v, the total area around the fountain that gets wet is

  1. πv4/2g2
  2. πv2/g2
  3. πv4/g2
  4. πv2/g
4

A boy can throw a stone up to a maximum height of 10 m. The maximum horizontal distance that the boy can throw the same stone up to will be

  1. 10 m
  2. 20√2 m
  3. 20 m
  4. 10√2 m
5

A lift is moving down with acceleration a. A man in the lift drops a ball inside the lift. The acceleration of the ball as observed by the man in the lift and a man standing stationary on the ground are respectively

  1. g, g
  2. a, g
  3. g-a, g-a
  4. g-a, g
6

A particle has an initial velocity of 3i + 4j and an acceleration of 0.4i + 0.3j. Its speed after 10s is

  1. 7(√2) units
  2. 10 units
  3. 7 units
  4. 8.5 units