A ball of 12 kg is attached to a string of 0.8 meter spun at 4

xenn [34]

Nuclear fission formula by the looks of it. Possibly how Professor Lisa Meitner realised that she had split the atomic nucleus. The Xenon and the Strontium (Xe and Sr) would presumably show up in a radio chemical assaying test at her university.
A few years later, Professor J Robert Oppenheimer watched a nuclear test somewhere near Los Alamos, US and lamented "I am become death, the destroyer of worlds". Shortly thereafter, Hiroshima and Nagasaki were razed to the ground and annihilated by nuclear bombs. Professor Meitner, probably inadvertently, had got the keys to the doors to "nuclear hell", and JRO ended up turning them. Something like that maybe, and a very harrowing and tumultuous period in human history.
Note in the fission equation, that out come two neutrons. They go off and produce a similar fission in another U235 nucleus into a chain reaction which, i not moderated by, say, Boron, can end up as a "mushroom cloud".

8 0

2 years ago

A 1.0 kg football is given an initial velocity at ground level of 20.0 m/s [37 above horizontal]. It gets blocked just after re

stepan [7]

Refer to the diagram shown below.

Neglect air resistance.
The horizontal component of the launch velocity is
(20 m/s)*cos(37°) = 15.973 m/s
The vertical component of the launch velocity is
(20 m/s)*sin(37°) = 12.036 m/s

The acceleration due to gravity is g =9.8 m/s².
The time, t s, for the ball to reach a height of 3 m is given by
(12.036 m/s)*(t s) - (1/2)*(9.8 m/s²)*(t s)² = (3 m)
12.036t - 4.9t² - 3 = 0
2.4543t - t² - 0.6122 = 0
t² - 2.4563t + 0.6122 = 0
Solve with the quadratic formula.
t = (1/2)[2.4563 +/- √(6.0334 - 2.4488)]
t = 2.1748 or 0.2815 s
The ball reaches a height of 3 m twice.
The first time it reaches 3 m height is 0.2815 s.

Part a.
The vertical velocity when t = 0.2815 s is
Vy = 12.036 - 9.8*0.2815
= 9.2773 m/s
The horizontal component of velocity is Vx = 15.973 m/s
The resultant velocity is
√(9.2773² + 15.973² ) = 18.47 m/s
Answer:
The velocity at a height of 3.0 m is 18.5 m/s (nearest tenth)

Part b.
The horizontal distance traveled is
d = (15.973 m/s)*(0.2815 s) = 4.4964 m
Answer:
The horizontal distance traveled is 4.5 m (nearest tenth)

6 0

2 years ago

Plans used for work that has to do with construction in or around earth are called

attashe74 [19]

Plans used for work that has to do with construction in or around Earth are called, “Civil Plans.”

Hope this helped!

7 0

3 years ago

Is NaCH an element? Why or why not?

amm1812

<span>NaCH is not an element, it is a compound. An element can be found and identified on the periodic table to elements. A compound is a combination of two of more elements. NaCH is composed of three elements: Na (sodium), C (carbon) and H (hydrogen), making it a compound.</span>

3 0

3 years ago

The current in a hair dryer measures 19 amps. The resistance of the hair dryer is 14 ohms. What is the voltage?

Masja [62]

Voltage = (current) x (resistance)

= (19 A) x (14 ohms) = 266 volts .

Note: Be careful using that thing !

It's dissipating

I² R = (19 A)² x (14 ohms) = 5,054 watts ! ! !

That's an awful lot of power for a blow-dryer !

The dryer is certainly not using very much of that power to run the fan.
Most of it is being used to heat air. 5 kilowatts is more power than most
toasters or microwave ovens use, so please be careful with how much of
your hair or skin you expose to that hot-air blast. You could probably cook
a meatloaf with it.

6 0

3 years ago