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A ball rolls off the top of a stairway with horizontal velocity u. The steps are 0.1 m high and 0.1 m wide. The minimum velocity u with which that ball just hits the step 5 of the stairway will be x m s-1, where x=_______ [use g=10 m s-2].

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Important Questions on Kinematics

MEDIUM
A shell is fired from a fixed artillery gun with an initial speed u such that it hits the target on the ground at a distance R from it. If t1 and t2 are the values of the time taken by it to hit the target in two possible ways, the product t1t2 is:
MEDIUM
A projectile is fired from the surface of the earth with a velocity of 5 m s-1 and angle θ with the horizontal. Another projectile fired from another planet with a velocity of 3 m s-1 at the same angle follows a trajectory which is identical with the trajectory of the projectile fired from the earth. The value of the acceleration due to gravity on the planet is: (given =9.8 m s-2)
MEDIUM
Two particles are projected from the same point with the same speed u such that they have the same range R, but different maximum heights, h1 and h2. Which of the following is correct?
HARD
The horizontal range and maximum height attained by a projectile are R and H respectively. If a constant horizontal acceleration a=g4 is imparted to the projectile due to wind, then its horizontal range and maximum height will be 
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Two guns A and B can fire bullets at speeds 1 km s-1 and 2 km s-1 respectively. From a point on a horizontal ground, they are fired in all possible directions. The ratio of maximum areas covered by the bullets fired by the two guns, on the ground is:
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At what angle θ to the horizontal should an object is projected so that the maximum height reached is equal to the horizontal range?
HARD
A plane is inclined at an angle α=30° with respect to the horizontal. A particle is projected with a speed  u=2 m s-1 , from the base of the plane, making an angle θ=15° with respect to the plane as shown in the figure. The distance from the base, at which the particle hits the plane is close to:
(Take  g=10 m s-2 )
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Two projectiles A and B are projected with the same initial speed. A is launched at an angle ϕ with the horizontal and B at an angle ϕ with the vertical. If A has a range R1 and B has a range R2, then
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A boy is standing on top of a tower of height, 85 m and throws a ball in the vertically upward direction with a certain speed. If 5.25 s later he hears the ball hitting the ground, then the speed with which the boy threw the ball is (take g=10 m s-2, the speed of sound in air is 340 m s-1)
MEDIUM
The position of a projectile launched from the origin at t = 0 is given by r = 4 i ^ + 5 j ^ m   at t = 2s. If the projectile was launched at an angle θ  from the horizontal, then θ   is (take g = 10 ms-2).
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The velocity of a projectile at the initial point A is 2i^-3j^ m s-1. Its velocity (in m s-1) at point B is

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Two bodies are projected at angles θ and 90o-θ to the horizontal with the same speed. The ratio of their times of flight is
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A projectile is given an initial velocity of i^+3 j^ m s-1, where i^ is along the ground and j^ is along the vertical. Then, the equation of the path of projectile is [Take, g=10 m s-2
MEDIUM
Two balls are projected at an angle θ and (90°-θ) with respect to the horizontal with the same speed. The ratio of their maximum vertical heights is
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Four projectiles are fired with the same velocities at angles 25°,40°,55° and 70° with the horizontal. The range of projectile will be largest for the one projected at angle _____.
HARD
A particle aimed at a target, projected at an angle 15° with the horizontal is short of the target by 10 m. If the same particle projected at an angle of 45° with the horizontal then it is away from the target by 15 meters. The angle of projection to hit the target is
MEDIUM
A ball is dropped from a height H from rest. The ball travels H2 in last 1.0 s. The total time taken by the ball to hit the ground is
MEDIUM
When an object is shot from the bottom of a long smooth inclined plane kept at an angle 60° with horizontal, it can travel a distance x1 along the plane. But, when the inclination is decreased to 30° and the same object is shot with the same velocity, it can travel x2 distance. Then x1:x2 will be
HARD
A small boy is throwing a ball towards a wall 6 m in front of him. He releases the ball at a height of 1.4 m from the ground. The ball bounces from the wall at a height of 3 m, rebounds from the ground and reaches the boy's hand exactly at the point of release. Assuming the two bounces (one from the wall and the other from the ground) to be perfectly elastic, how far ahead of the boy did the ball bounce from the ground?
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A projectile is given an initial velocity of i^+2j^ m s-1, where i ^ is along the ground and j ^ is along the vertically upward direction. If g=10 m s-2, the equation of its trajectory is :