210 Pb ---> -ie + 210 B:
84 8.3
We must remember that the total net force equation at
constant velocity is:
<span>F – Ff = 0</span>
of
F - µN = 0
Using Newton's 2nd Law of Motion:<span>
F = m a
<span>Where,
F = net force acting on the body
m = mass of the body
a = acceleration of the body
Since the cart is moving at a constant velocity, then
acceleration is zero, hence the working equation simplifies to
F = net Force = 0
Therefore,
F - µN = 0
where
µ = coefficient of friction = 0.20
N = normal force acting on the cart = 12 N
Therefore,
F - 0.20(12) = 0
<span>
F = 2.4 N </span></span></span>
Answer:So the answer is B
Explanation: When the light rays either bend or change their direction while passing from one medium to another it is called refraction of light. The refraction of light takes place when light travels from air into glass, from glass into air, from air into water or from water into air.
Answer:
3.5 hours
Explanation:
Speed = distance/time
Let the distance that Fiora biked at 20 mi/h through be x miles and the time it took her to bike through that distance be t hours at 20 mi/h
Then, the rest of the distance that she biked at 14 mi/h is (112 - x) miles
And the time she spent biking at 14 mi/h the rest of the distance = (6.5 - t) hours
Her first biking speed = 20 mph = 20 miles/hour
Speed = distance/time
20 = x/t
x = 20 t (eqn 1)
Her second biking speed = 14 mph = 14 miles/hour
14 = (112 - x)/(6.5 - t)
112 - x = 14 (6.5 - t)
112 - x = 91 - 14t (eqn 2)
Substitute for x in (eqn 2)
112 - 20t = 91 - 14t
20t - 14t = 112 - 91
6t = 21
t = 3.5 hours
x = 20t = 20 × 3.5 = 70 miles.
(112 - x) = 112 - 70 = 42 miles
(6.5 - t) = 6.5 - 3.5 = 3 hours
Meaning that she travelled at 20 mi/h for 3.5 hours.
Those organic structures that do not seem to play any important biological function in the organism that possesses them are known as vestigial structures.
<h2>What is a vestigial structure?</h2>
A vestigial structure is one that has atrophied or lost its original function throughout the course of evolution.
- It generally refers to those organic structures that were useful at some point, but are now practically or totally useless.
- These structures are preserved as an inheritance of the evolutionary process, because at some point an ancestor of the current species had that structure, which was functional, but it ceased to be important and would end up atrophy.
Therefore, we can conclude that vestigial structures are structures that some organisms still conserve as an inheritance from their ancestors but that, for some reason or another, are no longer useful for the functioning of the same.
Learn more about vestigial structures here: brainly.com/question/2141655
