A 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)

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Question

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)

Solution

Correct option is

(85.56 m/s, 746.9 m)

The speed of the car v = 72 × (5/18) = 20 m/s. The time of flight of projectile

 

And range of projectile  

According to given problem,

                                    R = 500 + vT

Substituting the values of T and R from Eqns. (1) and (2) in the above,

                          

As negative sign is physically unacceptable,

       u = 10 [1.414 + 7.14] = 85.56 m/s.

Substituting the above value of u in Eqn. (2),

           

SIMILAR QUESTIONS

Q1

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Q2

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

Q3

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

Q4

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

Q5

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

Q6

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Q7

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Q8

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Q9

 

A gun is fired from a moving platform and the ranges of the shot are observed to be R and when platform is moving forward or

backward respectively with velocity V. find the elevation of the gun is

Q10

Particles P and Q of mass 20 g and 40g respectively are simultaneously projected from points A and B on the ground. The initial velocities of Pand Q make 45° and 135° angles respectively with the horizontal AB as shown in the figure. Each particle has an initial speed of 49 m/s. The separation AB is 245 m. Both particles travel in the same vertical and plane and undergo a collision. After collision P retraces its path. Determine the position of Q when it hits the ground. How much time after the collision does the particle Q take to reach the ground? (Take g = 9.8 m/s2)