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# Monthly Archives: October 2015

## Projectile motion

A person observe a bird on tree 39.6m high and at distance of 59.2m. With what velocity the person should throw an arrow at an angle of 45°so that it may hit the bird.

## momentum, inertia and an interesting question

Hello, I have asked several engineers this question but none of them can give me an answer.  my question is: Suppose we had two guns, one with a barrel length of 20 inches and one with a barrel length of 10 inches.  if they both fired the same type of bullet projectile with the necessary differing powder charge to give those bullet projectiles muzzle velocities of 3000 feet per second, from both guns, at the same time, would the bullet from the shorter barrel slow down first?

Thanks

Eddie

## boat crossing river relative velocity

During the entire motion of a boat crossing a river, what would be the minimum time to cross the river along the shortest path possible? (I.e., considering both minimum time and shortest distance of approach)

## Resultant Velocity – A motor boat is racing towards north

A motor boat is racing towards north at 25kmh-1 and the water current in that region is 10kmh-1 in the direction of 60° east of south. Find the resultant velocity of the boat.

## Calculate the force on the Hammer

A hammer of mass 400 grams moving at a speed of 50 ms-1 strikes a nail . The nail stop the hammer for small interval of time i.e. 0.025 seconds . What is the change of momentum suffered by hammer also calculate the force of the hammer on the nail . What will be the force on hammer

## A stone is thrown from a bridge at an angle 30 degree with horizontal with a velocity 25m/s.If the stone strike the water surface after 2.5sec,calculate the height of bridge from the water surface.

A stone is thrown from a bridge at an angle 30 degree with horizontal with a velocity 25m/s.If the stone strike the water surface after 2.5sec,calculate the height of bridge from the water surface.

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