Friday, October 21, 2011

ASSIGNMENT HEIGHT & DISTANCE


_____________________HEIGHTS&DISTANCES_________________________________

  1. A tree breaks due to the storms and the broken part bends so that the top of the tree touches the ground making an angle 30° with the ground. The distance from the foot of the tree to the point where the top touches the ground is 10 metres. Find the height of the tree.
  2. A boy is standing on the ground and flying a kite with 100 m of string at an elevation of 30°. Another boy is standing on the roof of a 20 m high building and is flying his kite at an elevation of 45°. Both the boy are on opposite sides of both the kites. Find  the length of the string that the second boy must have so that the two kites meet.
  3. The shadow of a vertical tower on level ground increases by 10 metres, when the altitude of the sun changes from 45° to 30°. Find the height of the tower, correct to one place of decimal. ( take root 3  = 1.73
  4. A vertically straight tree, 15 m high, is broken by the wind in such a way that its top just touches the ground and makes an angle of 60° with the ground. At what height from the ground did the tree break?
  5. The angle of elevation of the top of a tower from a point A on the ground is 30°. On moving a distance of 20 metres towards the foot of the tower to a point B the angle of elevation increases to 60°. Find the height of the tower and the distance of the tower from the point A.
  6. The angle of elevation of an aeroplane from a point P on the ground is 60°. After a flight of 15 seconds, the angle of elevation changes to 30°. If the aeroplane is flying at a constant height of 1500 root 3 m, find the speed of the aeroplane.
  7. The angle of elevation, q of a vertical tower from a point on ground is such that its tangent is5/12 . On walking 192 metres towards the tower in the same straight line, the tangent of the angle of elevation,  is found to be 3/4 . Find the height of the tower.
  8. A man on the deck of a ship is 16 m above water level. He observes that the angle of elevation of the top of a cliff is 45° and the angle of depression of the base is 30°. Calculate the distance of the cliff from the shop and the height of the cliff.
  9. A round balloon of radius a subtends an angle q at the eye of the observer while the angle of elevation of its center is . Prove that the height of the center of the balloon is a sin  cosec .
  10. The shadow of a tower is three times as long as the shadow of the tower when the  sun says meet the ground at an angle of 60°. Find the angle between the sun rays and the ground at the time of longer shadow.
  11. A  ladder is placed against a wall such that it just reaches the top of the wall. The foot of the ladder is 1.5 m away from the wall and the ladder is inclined at an angle of 60° with the ground. Find the height of the wall.
  12. A man is standing on the deck of a ship, which is 8 m above water level. He observes the angle of elevation of the top of a hill as 60° and the angle of  depression of the base of the hill is 30°. Calculate the distance of the hill from the ship and the height of the hill.
  13. From the foot of a hill, the angle of elevation of the top of a tower is found to be 45°. After walking 2 km upwards along the slope of the hill which is inclined at 30° , the same is found to be 60°. Find the height of the tower.
  14. There is a small island is the middle of a 100 m wide river and a tall tree stands on the island. P and Q are points directly opposite each other on the two banks and in line with the tree. If the angles of elevation of the top of the tree from P and Q are respectively 30° and 45°, find the height of the tree.