Home
Class 11
PHYSICS
A person sees an object on a tree at a h...

A person sees an object on a tree at a heitht of ` 40 m` and at a distance of ` 60 m` . Whith what velocity he showld throw an arrow at an angle of `45^@` so that it may hit the object ? Take ` g= 10 ms^(2)`.

Text Solution

Verified by Experts


For horizontal motion of bullet:
`x=ucos 45^(@)xxt`
`rArr 60=u xx(l)/(sqrt2)`
or `u=(60)sqrt2/(t)`
For vertical motion of bullet :
`y=(u sin 45^(@))t-(1)/(2)gt^(2)`
`rArr 40=((60sqrt2)/(t))((1)/(sqrt2)t)-(1)/(2)(9.8t^(2))`
`rArr t^(2)=(60-40)/(4.9)=(20)/(4.9)=4.082`
`rArr t=2.02s`
`therefore u=(60sqrt2)/(t)`
`=(60xx1.414)/(2.02)=42m//s`
Promotional Banner

Topper's Solved these Questions

  • MOTION IN A PLANE

    MODERN PUBLICATION|Exercise PRACTICE PROBLEMS (1)|8 Videos

  • MOTION IN A PLANE

    MODERN PUBLICATION|Exercise PRACTICE PROBLEMS (2)|9 Videos

  • MECHANICAL PROPERTIES OF FLUIDS

    MODERN PUBLICATION|Exercise Chapter Practise Test|16 Videos

  • MOTION IN A STRAIGHT LINE

    MODERN PUBLICATION|Exercise CHAPTER PRACTICE TEST|16 Videos

Similar Questions

Explore conceptually related problems

A person observes a bird on a tree 39.6 m high and at a distance of 59.2 m. With what velocity the person should throw an arrow at an angle of 45^(@) so that it may hit the bird ?

A person throws a bottle into a dustbin at the same height as he is 2m away at an angle of 45^(@) .The velocity of thrown is

An object takes 15 s to reach the ground from a height of 40 m on a planet. What is the value of g on the planet ?

An object is thrown towards the tower which is at a horizontal distance of 50 m with an initial velocity of 10 ms^(-1) and making an angle 30^(@) with the horizontal. The object hits the tower at certain height. The height from the bottom of the tower, where the object hits the tower is (Take, g = 10 ms^(-2))

A projectile is thrown with a velocity of 20 m//s, at an angle of 60^(@) with the horizontal. After how much time the velocity vector will make an angle of 45^(@) with the horizontal (in upward direction) is (take g= 10m//s^(2))-

A football is kicked with speed 20 ms^(-1) at a projection angle of 45^@ from the ground. A receiver on the goal line 20 m away in the disrection of the kich runs the same instant to meet the ball. What must he his speed, of he is to catch the ball cefore it hits the ground ? Take g= 10 ms^(-2) .

A gun kept on a straight horizontal road is used to hit a car travelling on the same road away from the gun at a uniform speed of 10sqrt(2)ms^(-1) .The car is at a distance of 150m from the gun when it is fired at an angle of 45^(@) to the horizontal.With what speed should the shell be projected so that it hits the car? Take g=10ms^(-2)

What are the angles of projection of a projectile projected with velocity 30 ms^(-1) , so that the horizontal range is 45 m ? Take g = 10 ms^(-2) .

At what angle should a body he projected with a velocity 24 ms^(-1) just to pass over the obstacle 14 m high at a distance of 24 m [Take g = 10ms^(-2) ]