Answer:
H = start height (v = 0)
h = present height
v = present speed
assuming no friction
total energy = PE + KE
mgH = mgh + .5mv^2
if PE = KE then
mgH = mgh + mgh
h = H/2
potential energy = kinetic energy when object is at half its start height.
Explanation:
The distance an object falls from rest through gravity is
D = (1/2) (g) (t²)
Distance = (1/2 acceleration of gravity) x (square of the falling time)
We want to see how the time will be affected
if ' D ' doesn't change but ' g ' does.
So I'm going to start by rearranging the equation
to solve for ' t '.
D = (1/2) (g) (t²)
Multiply each side by 2 : 2 D = g t²
Divide each side by ' g ' : 2 D/g = t²
Square root each side: t = √ (2D/g)
Looking at the equation now, we can see what happens
to ' t ' when only ' g ' changes:
-- ' g ' is in the denominator; so bigger 'g' ==> shorter 't'
and smaller 'g' ==> longer 't' .
-- They don't change by the same factor, because 1/g is inside
the square root. So 't' changes the same amount as √1/g does.
Gravity on the surface of the moon is roughly 1/6 the value
of gravity on the surface of the Earth.
So we expect ' t ' to increase by √6 = 2.45 times.
It would take the same bottle (2.45 x 4.95) = 12.12 seconds
to roll off the same window sill and fall 120 meters down to the
surface of the Moon.
Answer:
A. More than 20% of your daily recommended amount.
Explanation:
Reading food labels can be tricky. The percent daily value listed on the right of all food labels lets you know what percent out of the recommended daily intake of each nutrient you are consuming in that specific food.
To check if the food you're consuming is a good source of that nutrient you need in higher amount, the nutrient must be labeled 20% or higher.
The rule used here is called the 5/20 rule. According to this rule, A nutrient that is 5% or below is considered less and a nutrient which is labeled 20% or higher is considered good enough in that food source.
Energy that is applied to an object.
--TheOneandOnly003
<span>A 67.0 kg crate is being raised by means of a rope. Its upward acceleration is 3.50 m/s2. What is the force exerted by the rope on the crate?
</span>Newton's Second Law<span> of Motion states, “The force acting on an object is equal to the mass of that object times its acceleration.” We calculate as follows:
</span>
F = ma = 67.0 kg (3.50 m/s^2) = 234.5 J
