A certain airplane has a speed ofand is diving at an angle ofbelow the horizontal when the pilot releases a radar decoy (Fig. 4-33). The horizontal distance between the release point and the point where the decoy strikes the ground is(a) how long is the decoy in the air? (b)How high was the release point?
(a) The decoy is in the air for
(b) The release point washigh.
Initial speed of airplane is
Projection angle is below the horizontal.
Horizontal distance between release point of the decoy and the point where decoy strike the ground is
This problem deals with kinematic equations that describe the motion of an object with constant acceleration. Using the standard equation for the velocity of the object, the time that the decoy spent in air can be computed. Further, using the formula for the second kinematic equation, the height of release point can be found.
The displacement for the horizontal and vertical direction can be written as,
Now, using equation (i) the time will be,
A golfer tees off from the top of a rise, giving the golf ball an initial velocity of 43.0 m/s at an angle of above the horizontal. The ball strikes the fairway a horizontal distance of 180 m from the tee. Assume the fairway is level. (a) How high is the rise above the fairway? (b) What is the speed of the ball as it strikes the fairway?
A baseball is hit at Fenway Park in Boston at a point 0.762 m above home plate with an initial velocity of 33.53 m/s directed above the horizontal. The ball is observed to clear the 11.28-m- high wall in left field (known as the “green monster”) 5.00 s after it is hit, at a point just inside the left-field foulline pole. Find (a) the horizontal distance down the left-field foul line from home plate to the wall; (b) the vertical distance by which the ball clears the wall; (c) the horizontal and vertical displacements of the ball with respect to home plate 0.500 s before it clears the wall.
Long flights at mid-latitudes in the Northern Hemisphere encounter the jet stream, an eastward airflow that can affect a plane’s speed relative to Earth’s surface. If a pilot maintains a certain speed relative to the air (the plane’s airspeed), the speed relative to the surface (the plane’s ground speed) is more when the flight is in the direction of the jet stream and less when the flight is opposite the jet stream. Suppose a round-trip flight is scheduled between two cities separated by 4000 km, with the outgoing flight in the direction of the jet stream and the return flight opposite it.The airline computer advises an airspeed of 1000 km/hr, for which the difference in flight times for the outgoing and return flights is 70.0 min.What jet-stream speed is the computer using?
A baseball leaves a pitcher’s hand horizontally at a speed of . The distance to the batter islocalid="1654591573193" . (a)How long does the ball take to travel the first half of that distance? (b) The second half? (c)How far does the ball fall freely during the first half? (d) During the second half? (e)Why aren’t the quantities in (c) and (d) equal?
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