Answer:
A: 1.962
B: 3.924
Explanation:
g = G *M /R^2
g = 9.807*M/R^2 the gravitational constant of ground level on earth is about 9.807
g = 9.807*5lbs/R^2 the average brick is about 5 pounds.
g = 9.807*5*10^2. I'm assuming the height is around ten feet to help you out.
with these numbers plugged in you get an acceleration of 0.4905 a final velocity after 4 seconds 1.962. It's height fallen after 4 seconds is 3.924.
( M = whatever the brick weighs it's not specified in the question)
(R = the distance from the ground or how high the scaffold is)
(hopefully you can just plug your numbers in there hope this helps)
Complete question is: While running, a person dissipates about 0.60 J of mechanical energy per step per kilogram of body mass. If a 60-kg person develops a power of 70 W during a race, how fast is the person running? (Assume a running step is 1.5 m long).
Answer: The person running at a speed of 2.91 m/s.
Explanation:
Given: Mass of runner = 60 kg
Runner dissipates = 0.6 J/kg per step
Average power = 70 W
1 step = 1.50 m
Energy dissipated by the runner is as follows.
![\Delta E_{step} = 0.60 \times 60\\= 36 J](https://tex.z-dn.net/?f=%5CDelta%20E_%7Bstep%7D%20%3D%200.60%20%5Ctimes%2060%5C%5C%3D%2036%20J)
Formula used to calculate the value of one step 'S' is as follows.
![\frac{S}{\Delta t} = \frac{P_{avg}}{\Delta E_{step}} = \frac{70}{36}\\= 1.94\\S = 1.94 \Delta t](https://tex.z-dn.net/?f=%5Cfrac%7BS%7D%7B%5CDelta%20t%7D%20%3D%20%5Cfrac%7BP_%7Bavg%7D%7D%7B%5CDelta%20E_%7Bstep%7D%7D%20%3D%20%5Cfrac%7B70%7D%7B36%7D%5C%5C%3D%201.94%5C%5CS%20%3D%201.94%20%5CDelta%20t)
It is known that average velocity is equal to the total distance divided by time interval.
So, total distance for the given situation is as follows.
![d = S \times 1.5](https://tex.z-dn.net/?f=d%20%3D%20S%20%5Ctimes%201.5)
Hence, speed of the person is calculated as follows.
![v_{avg} = \frac{d}{\Delta t}\\= \frac{S \times 1.5}{\Delta t}\\= \frac{1.94 \Delta t \times 1.5}{\Delta t}\\= 2.91 m/s](https://tex.z-dn.net/?f=v_%7Bavg%7D%20%3D%20%5Cfrac%7Bd%7D%7B%5CDelta%20t%7D%5C%5C%3D%20%5Cfrac%7BS%20%5Ctimes%201.5%7D%7B%5CDelta%20t%7D%5C%5C%3D%20%5Cfrac%7B1.94%20%5CDelta%20t%20%5Ctimes%201.5%7D%7B%5CDelta%20t%7D%5C%5C%3D%202.91%20m%2Fs)
Thus, we can conclude that the person running at a speed of 2.91 m/s.
Answer:
An electric current is a flow of particles (electrons) flowing through wires and components. It is the rate of flow of charge. If the electric charge flows through a conductor, we say that there is an electric current in the conductor. In the circuits using metallic wires, electrons constitute a flow of charges.
Answer:
I know 1, that is in the case of a burning of a candle.
Explanation:
To solve this problem it is necessary to apply the concepts related to the Period based on the length of its rope and gravity, mathematically it can be expressed as
![T= 2\pi \sqrt{\frac{L}{g}}](https://tex.z-dn.net/?f=T%3D%202%5Cpi%20%5Csqrt%7B%5Cfrac%7BL%7D%7Bg%7D%7D)
g = Gravity
L = Length
T = Period
Re-arrange to find the gravity we have
![g = \frac{4\pi^2 L}{T^2}](https://tex.z-dn.net/?f=g%20%3D%20%5Cfrac%7B4%5Cpi%5E2%20L%7D%7BT%5E2%7D)
Our values are given as
![L = 0.35m\\T = 2s\\](https://tex.z-dn.net/?f=L%20%3D%200.35m%5C%5CT%20%3D%202s%5C%5C)
Replacing we have
![g = \frac{4\pi^2 L}{T^2}](https://tex.z-dn.net/?f=g%20%3D%20%5Cfrac%7B4%5Cpi%5E2%20L%7D%7BT%5E2%7D)
![g = \frac{4\pi^2 0.35}{2^2}](https://tex.z-dn.net/?f=g%20%3D%20%5Cfrac%7B4%5Cpi%5E2%200.35%7D%7B2%5E2%7D)
![g = 3.45 m/s^2](https://tex.z-dn.net/?f=g%20%3D%203.45%20m%2Fs%5E2)
Therefore the correct answer is C.