Answers:
a) 5400000 J
b) 45.92 m
Explanation:
a) The kinetic energy 
of an object is given by:
Where:
is the mass of the train
is the speed of the train
Solving the equation:
This is the train's kinetic energy at its top speed
b) Now, according to the Conservation of Energy Law, the total initial energy is equal to the total final energy:
Where:
is the train's initial kinetic energy
is the train's initial potential energy
is the train's final kinetic energy
is the train's final potential energy, where 
is the acceleration due gravity and 
is the height.
Rewriting the equation with the given values:
Finding :
Answer: Gravity is the force that keeps planets in orbit around the Sun. Gravity alone holds us to Earth's surface.
Planets have measurable properties, such as size, mass, density, and composition. A planet's size and mass determines its gravitational pull.
A planet's mass and size determines how strong its gravitational pull is.
Models can help us experiment with the motions of objects in space, which are determined by the gravitational pull between them.
Explanation:
<span>0.52%
First, let's convert that speed into m/s.
150 km/h * 1000 m/km / 3600 s/h = 41.667 m/s
Now let's see how much time gravity has to work on the ball. Divide the distance by the speed.
18 m / 41.667 m/s = 0.431996544 s
Now multiply that time by the gravitational acceleration to see what the vertical component to the ball's speed that gravity adds.
0.431996544 s * 9.8 m/s^2 = 4.233566131 m/s
Use the pythagorean theorem to get the new velocity of the ball.
sqrt(41.667^2 + 4.234^2) = 41.882 m/s
Finally, let's see what the difference is
(41.882 - 41.667)/41.667 = 0.005159959 = 0.5159959%
Rounding to 2 figures, gives 0.52%</span>
Answer:
TIME he applied the fertilizer to each plant
Explanation:
Independent variable in an experiment is the variable that is subject to change or manipulation by the experimenter. In this experiment, Bob wanted to investigate the effects of plant fertilizer. Bob sets up the experiment by applying the fertilizer to each plant at DIFFERENT TIMES i.e. plant 1-every morning, plant 2-once a week, plant 3-never.
Based on this, it is obvious that the independent or manipulated variable is the TIME at which he applied the fertilizer. On the other hand, the dependent or measured variable is the height of the plants.
Answer:
i found this provided by the San Francisco 49ers (found on Khan Academy)
Explanation:
I HOPE THIS HELPS!!!
So, what is a force? A force is a push or a pull exerted on one object from another. Forces make things move. You can make something start or stop when you push or pull an object.
There are many different types of forces in action in football. A player kicking a football is a force that makes the football fly through the air. A quarterback throwing a football is another example of a force that makes the football fly in a game.
When studying the concept of force, we can look to history to find mathematical principles that guide the laws of motion. Sir Isaac Newton was one of the most famous scientists of the 17th century to study the laws of forces and motion. Through careful study of how objects react to various forces, Newton developed the Three Laws of Motion. Below are explanations of each law and how these laws can be applied to football.
