Question

The maximum height attained by a projectile is increased by 10% by changing the angle of projection, without changing the speed of projection. The percentage increase in the time of flight will be

Solution

Correct option is

5%

Given  differentiating partially we get

(∵ v0 = constant)

Hence T increases by 5%.

SIMILAR QUESTIONS

Q1

missile is fired for maximum range at your town from a place in the enemy country 100 km away from your town. If the missile is first detected at its half – way point, how much warning time will you have? Take g = 10 ms-2.

Q2

cricketer can throw a ball to a maximum horizontal distance of 100 m. With the same effort, he throws the ball vertically upwards. What is the maximum height attained by the ball?

Q3

From the top of a tower of a height 40 m, a ball is projected upwards with a speed of 20 m/s at an angle of elevation of 30°. The ratio of the total time taken by the ball to hit the ground to its time of flight (time taken to come back to the same elevation) is (Take g = 10 m/s2)

Q4

The maximum height attained by a projectile is increased by 10% by increasing its speed of projection, without changing the angle of projection. The percentage increase in the horizontal range will be

Q5

The speed of projection of projectile is increased by 5%, without changing the angle of projection. The percentage increase in the range will be

Q6

A projectile has the same range R when the maximum height attained by it is either h1 or h2. Then Rh1 and h2 will be related as

Q7

A relief aeroplane is flying at a constant height of 1960 m with speed 600km/hr above the ground towards a point directly over a person struggling in flood water (see fig.). At what angle if sight, should the pilot release a survival kit if it is to reach the person is water? (g = 9.8 m/s2

                                               

Q8

At a harbour enemy ship is at a distance  from the security cannon having a muzzle velocity of 60 m/s (a) To what angle must the cannon be elevated to hit the ship? (b) What is the time of flight? (c) How far should the ship be moved away from its initial position so that it becomes beyond the range of the cannon? (g = 10 m/s2)

Q9

During volcanic eruption chunks of solid rock are blasted out of the volcano. (a) At what initial speed would a volcanic object have to be ejected at 37° to the horizontal from the vent A in order to fall at B as shown in fig. (b) What is the time of flight? (g = 9.8 m/s2)

                                                  

Q10

gun, kept on a straight horizontal road, is used to hit a car travelling along the same road away from the gun with a uniform speed of 72 km/hr. The car is at a distance is 500 m from the gun, when the gun is fired at an angle of 45° with the horizontal. Find (a) the distance of the car from the gun when the shell hits it; (b) the speed of projection of the shell from the gun. (g = 9.8 m/s2)