Answer:
B. the boy is not lifting more than 1m up, as the question states
To determine the answer to this item, we use two (2) equations.
Equation for kinetic energy:
KE = 0.5 mv²
Equation for momentum:
P = mv
From the second equation, we can deduced that,
m = P/v
Substituting the known values from the given above,
m = 30/v
Using this expression in the first equation,
KE = 0.5 mv²; 150 = 0.5(30/v)(v²)
The value of v from the equation is 10 m/s.
The mass is therefore calculated as such,
m = 30/v = 30/10 = 3 kg
Hence, the answers are,
<em> Mass = 3 kg</em>
<em> Velocity = 10 m/s</em>
Answer:
The elastic potential is 1/2 as much.
Explanation:
The reason I say this is because of you take a new rubber band, after stretching the first time, all the way until it doesn't snap, you stretch it again and there's not as much resistance as when it was new.
I hope this helps.
Answer:
The bond energy of F–F = 429 kJ/mol
Explanation:
Given:
The bond energy of H–H = 432 kJ/mol
The bond energy of H–F = 565 kJ/mol
The bond energy of F–F = ?
Given that the standard enthalpy of the reaction:
<u>H₂ (g) + F₂ (g) ⇒ 2HF (g)</u>
ΔH = –269 kJ/mol
So,
<u>ΔH = Bond energy of reactants - Bond energy of products.</u>
<u>–269 kJ/mol = [1. (H–H) + 1. (F–F)] - [2. (H–F)]</u>
Applying the values as:
–269 kJ/mol = [1. (432 kJ/mol) + 1. (F–F)] - [2. (565 kJ/mol)]
Solving for , The bond energy of F–F , we get:
<u>The bond energy of F–F = 429 kJ/mol</u>
Answer:
Explanation:
In physics, work can be described as force multiplied by the displacement of the object (distance caused by the force acted on the object).
Work is a form of energy, therefore, it is measured in joules.
If Alex pushed on an object with 10N of force, and the object moved 2 meters, the work of Alex will be equal to:
W = Ft
W = 10N * 2m
W = 20 Joules
But, if we have John, that pushed on an object with 2N of force, but, since the object was way smaller, therefore it had way less inertia, the object moved a distance equal to 10 meters. Let's also calculate his work.
W = Ft
W = 2N * 10m
W = 20 Joules
And we got the same result.
Work can also be used to calculate power.
Power is equal to P = Work / time
It can also be written as P = delta Work / delta time
Power is measured in joules per second.
With power you can make the difference between someone that got a 2 kg object up in 2 second, and someone that got a 2 kg object up in 5 second.
The more powerful one would be the one who managed to make the same work in less time.
Hope it Helped!