1. At a horizontal distance of 45m from a tree, the angle of elevation to the to
ID: 2132817 • Letter: 1
Question
1. At a horizontal distance of 45m from a tree, the angle of elevation to the top of the tree is 26 degrees. How tall is the tree?
2. An arrow is shot straight up in the air at an initial speed of 15 m/s. After how much time is the arrow heading downward at a speed of 8 m/s?
3. One drop of oil falls straight down onto the road from the engine of a moving car every 5s. What is the average speed of the car over 600m where there are a total of 6 drops?
4. When applying the equations of kinematics for an object moving in one dimension, which of the following statements must be true? (a) The velocity of the object must remain constant. (b) The acceleration of the object must remain constant. (c) The velocity of the object must increase with time. (d) The position of the object must increase with time. (e) The velocity of the object must always be in the same direction as its acceleration.
5. An object moves along the x-axis, its position measured at each instant of time. The data are organized into an accurate graph of x vs. t. Which of the following quantities cannot be obtained from this graph? (a) The velocity at an instant. (b) The acceleration at any instant. (c) The displacement during some time interval. (d) The average velocity during some time interval. (e) The speed of the particle at any instant.
6. A ball is thrown downward from the top of a 40m tower with an initial speed of 12 m/s. Assuming negligible air resistance, what is the speed of the ball just before hitting the ground?
7. A cruise ship sails due north at 4.5 m/s while a coast guard patrol boat heads 45 degrees north of west at 5.2 m/s. What is the velocity of the cruise ship relative to the patrol boat?
8. A skier leaves the end of a horizontal ski jump at 22 m/s and falls 3.2 m before landing. Neglecting friction, how far horizontally does the skier travel in the air before landing?
9. A catapult launches a large stone at a speed of 45 m/s at an angle of 55 degrees with the horizontal. What maxi mum height does the stone reach?
10. A student throws a heavy red ball horizontally from a balcony of a tall building with an initial speed. At the same time, a second student drops a lighter blue ball from the same balcony. Which of the following statements is true? (a) The blue ball reaches the ground first. (b) The balls reach the ground at the same instant. (c) The red ball reaches the ground first. (d) Both balls hit the ground with the same speed. (e) None of the statements are true.
Explanation / Answer
1.
45 times tan 26 = 21.9 meters
Original figures were given to 2 significant figures.
The answer should be given to the same degree of accuracy as the figures used for the calculation unless otherwise instructed.
Answer = 22 meters to 2 sig fig
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