-- The string is 1 m long. That's the radius of the circle that the mass is
traveling in. The circumference of the circle is (π) x (2R) = 2π meters .
-- The speed of the mass is (2π meters) / (0.25 sec) = 8π m/s .
-- Centripetal acceleration is V²/R = (8π m/s)² / (1 m) = 64π^2 m/s²
-- Force = (mass) x (acceleration) = (1kg) x (64π^2 m/s²) =
64π^2 kg-m/s² = 64π^2 N = about <span>631.7 N .
</span>That's it. It takes roughly a 142-pound pull on the string to keep
1 kilogram revolving at a 1-meter radius 4 times a second !<span>
</span>If you eased up on the string, the kilogram could keep revolving
in the same circle, but not as fast.
You also need to be very careful with this experiment, and use a string
that can hold up to a couple hundred pounds of tension without snapping.
If you've got that thing spinning at 4 times per second and the string breaks,
you've suddenly got a wild kilogram flying away from the circle in a straight
line, at 8π meters per second ... about 56 miles per hour ! This could definitely
be hazardous to the health of anybody who's been watching you and wondering
what you're doing.
Answer: 90 m/s, 70 m/s
Explanation:
Given
A car travels 100 m east for 4 seconds and then turn around
goes back west for 50m in 1 sec
Distance traveled in the east is 
Distance traveled in the west is 
Total distance
total displacement
total time 
Average speed
Average velocity
I believe it's B. the transmission of heat across matter
Total distance travelled by the car is 'd'
<span>distance trveled before the brakes were applied = v_o * t </span>
<span>distance travld with brakes = d - v_o*t </span>
<span>applying the formula: v^2 - u^2 = -2 a * s </span>
<span>=> 0 - v_o^2 = -2 * a_x * (d- v_o*t) </span>
<span>=> a_x = (v_o^2)/ ( 2 (d-v_o*t)</span>
Answer:
Solution
The atomic number of iodine (53) tells us that a neutral iodine atom contains 53 protons in its nucleus and 53 electrons outside its nucleus. Because the sum of the numbers of protons and neutrons equals the mass number, 127, the number of neutrons is 74 (127 − 53 = 74). Since the iodine is added as a 1− anion, the number of electrons is 54 [53 – (1–) = 54].
Check Your Learning
An ion of platinum has a mass number of 195 and contains 74 electrons. How many protons and neutrons does it contain, and what is its charge?
Answer:
78 protons; 117 neutrons; charge is 4+
