Answer:
(A) The maximum height of the ball is 40.57 m
(B) Time spent by the ball on air is 5.76 s
(C) at 33.23 m the speed will be 12 m/s
Explanation:
Given;
initial velocity of the ball, u = 28.2 m/s
(A) The maximum height
At maximum height, the final velocity, v = 0
v² = u² -2gh
u² = 2gh
(B) Time spent by the ball on air
Time of flight = Time to reach maximum height + time to hit ground.
Time to reach maximum height = time to hit ground.
Time to reach maximum height is given by;
v = u - gt
u = gt
Time of flight, T = 2t
(C) the position of the ball at 12 m/s
As the ball moves upwards, the speed drops, then the height of the ball when the speed drops to 12m/s will be calculated by applying the equation below.
v² = u² - 2gh
12² = 28.2² - 2(9.8)h
12² - 28.2² = - 2(9.8)h
-651.24 = -19.6h
h = 651.24 / 19.6
h = 33.23 m
Thus, at 33.23 m the speed will be 12 m/s
A front is defined as a "boundary" that separates two masses of different air densities. I am not entirely sure, but I think the answers are either C or D, but I'm mostly convinced it's option D.
"Free fall" is the motion of an object when gravity is the ONLY force
acting on it.
In true 'free fall' the speed of an object increases at a constant rate
for the total duration of the fall. The rate of increase, on or near the
Earth's surface, is 9.8 meters per second for each second of fall.
True free fall is almost impossible to observe in everyday life, because
whenever we see anything falling, it's almost always falling through air,
so gravity is NOT the only force acting on it. The friction due to the
motion through air works against the gravitational force. In many cases,
the result is that the object's speed eventually stops increasing and
becomes constant, at a speed often described with the faux technical,
high-fallutin' sounding phrase "terminal velocity". It must be understood
that 'terminal velocity' is NOT a property of gravity or of free fall, but is
only a result of falling through some surrounding stuff that interferes with
the process of true 'free fall'.
Food and drug administration (FDA) is used for protecting the public health in safety, security, drugs, biological products, and medicinal devices.
Explanation:
The U.S food and Drug Act tells about the sale of misbranded or adulterated food and drugs in interstate commerce and had a foundation for the nation's first consumer protection agency.
The federal law is passed to establish the quality standards for foods, drugs and medical devices manufactured and sold in U.S.
This act has a new consumer protection against unlawful cosmetics and medical devices and enhances the government's ability to enforce the law. The main goal of FDA is to make food and drug safe for public consumption.
Answer:
a. Microwaves—3 and infrared waves—1
Explanation:
Microwaves and infrared waves are both part of the electromagnetic spectrum, but they have different frequency and wavelength.
In particular:
- Microwaves are long-wavelength electromagnetic waves, with wavelength between 1 mm and 1 m. Their wavelength is longer than visible light
- Infrared waves are also long-wavelength electromagnetic waves, but their wavelength is shorter than microwaves: between 700 nm and 1 mm. Their wavelength is also longer than visible light.
The two types of waves are also used for different purposes. In particular:
- Infrared waves are emitted by any hot object, and their intensity depends on the temperature of the object. Therefore, they are used in astronomy to show the heat released by astronomical objects (option 1)
- Microwaves are used to study the Cosmic Microwave Background (CMB). This is electromagnetic radiation that permeates the whole universe, and its wavelength depends inversely on the local temperature. Therefore, areas with longer wavelength have lower temperature, and viceversa. Therefore, microwaves are used to measure temperature differences in space (option 3).
