The AU ... Astronomical Unit ... used to be defined as the average distance between the Sun and Earth during the year.
Now it's defined as 149,597,870,700 meters exactly.
Answer:
1. D
2. B
Explanation:
This is because they are limited in quantity and available on Earth. if non- renewable resources are not conserved they will disappear during consumption.
Incomplete question.The complete question is
A 0.27 kg rock is projected from the edge of the top of a building with an initial velocity of 11.7 m/s at an angle 58 above the horizontal.
Due to gravity, the rock strikes the ground at a horizontal distance of 15.9 m from the base of the building. How tall is the building? Assume the ground is level and that the side of the building is vertical. The acceleration of gravity is 9.8 m/s
Answer:
Total height of the building =6.78 m
Explanation:
v = 11.7 m/s
Horizontal component of velocity = v x cos 58 = 11.7*cos 58 = 6.2 m/s
Total time of flight = Horizontal distance / Horizontal component of velocity = 15.9 / 6.2 = 2.56 sec.
Vertical component of velocity = v x sin 58 = 11.7 x sin 58 = 9.92 m/s
Time taken to reach maximum height = Vertical component of velocity / g = 9.92 / 9.81 = 1.01 sec.
Hence, Time taken to reach ground from maximum height = 2.56 - 1.01 = 1.55 sec.
Hence, Maximum height from ground = 0.5 x g x t^2 = 0.5 x 9.81 x 1.55^2 = 11.78 m
Maximum height from the top of building = 0.5 x 9.81 x 1.01^2 = 5 m
Hence, Total height of the building = 11.78 m - 5 m = 6.78 m
Answer:
(b) Net force causes change in motion.
Explanation:
There can be a motion even if there is no net force acting on an object.
It can be justified by giving an example:- when object is moving at constant speed then it has no net force and still is in motion.
If there is a net force acting, then the object will accelerate and this will cause change in motion.
The change in motion can be change in direction of motion, change in speed of motion.
For example when an object is moving in east direction if someone accelerate it this will result in change in motion or change in speed and after some time the net force is applies in the north direction then the object will move in the north direction which proves that the net force also causes change in direction.
