momentum= mass × velocity
p= 50×18
momentum= 900 kg m/s
Answer:
5,760
Explanation:
1 minute is equal to 60 seconds. so you will multiply 60 times 96. and that equals 5,760
Answer: Choice A) 0.44 miles
=================================================
Work Shown:
1 hour = 60 minutes
1 minute = 60 seconds
1 hour = 60*60 = 3600 seconds
40 seconds = 40*(1/3600) = 40/3600 = 1/90 hours
The car travels 1/90 of an hour. Let t = 1/90.
The initial velocity is vi = 30 mph.
The final velocity is vf = 50 mph.
Apply one of the kinematics equations as given below.
x = distance traveled
x = 0.5*(vi+vf)*t
x = 0.5*(30+50)*(1/90)
x = 0.44444444444444 which is approximate
x = 0.44
The car traveled roughly 0.44 miles. This matches with choice A.
I'm assuming choice A is supposed to say 0.44 instead of 0.442; otherwise, I think your teacher made a typo by putting that 2 in there. Each of the other answer choices are accurate to 2 decimal places, so it would make sense that choice A is also accurate to 2 decimal places as well.
If 0.442 was intended by your teacher, and it's not a typo, then the answer would be E) None of the choices given.
Answer:
510448 Joules
102089.6 J
13.61194 min
Explanation:
![1\ kcal=4184\ J](https://tex.z-dn.net/?f=1%5C%20kcal%3D4184%5C%20J)
![122\ cal=122\times 4184=510448\ J](https://tex.z-dn.net/?f=122%5C%20cal%3D122%5Ctimes%204184%3D510448%5C%20J)
The energy in Joules is 510448 Joules.
20% of energy
![0.2\times 510448=102089.6\ J](https://tex.z-dn.net/?f=0.2%5Ctimes%20510448%3D102089.6%5C%20J)
The energy is 102089.6 J
Power is given by
![P=\dfrac{E}{t}\\\Rightarrow t=\dfrac{E}{P}\\\Rightarrow t=\dfrac{102089.6}{125}\\\Rightarrow t=816.7168\ s=\dfrac{816.7168}{60}=13.61194\ min](https://tex.z-dn.net/?f=P%3D%5Cdfrac%7BE%7D%7Bt%7D%5C%5C%5CRightarrow%20t%3D%5Cdfrac%7BE%7D%7BP%7D%5C%5C%5CRightarrow%20t%3D%5Cdfrac%7B102089.6%7D%7B125%7D%5C%5C%5CRightarrow%20t%3D816.7168%5C%20s%3D%5Cdfrac%7B816.7168%7D%7B60%7D%3D13.61194%5C%20min)
The number of minutes is 13.61194 min
An average person consumes around 2000-2500 kcal
![0.2\times 122=24.4\ kcal](https://tex.z-dn.net/?f=0.2%5Ctimes%20122%3D24.4%5C%20kcal)
This is done in 13.61194 min
In one hour
![\dfrac{24}{13}\times 60=110.76923\ kcal](https://tex.z-dn.net/?f=%5Cdfrac%7B24%7D%7B13%7D%5Ctimes%2060%3D110.76923%5C%20kcal)
So, it is easy to consume the calories.
Answer:
The time is 16 min.
Explanation:
Given that,
Time = 120 sec
We need to calculate the moment of inertia
Using formula of moment of inertia
![I=\dfrac{1}{2}MR^2](https://tex.z-dn.net/?f=I%3D%5Cdfrac%7B1%7D%7B2%7DMR%5E2)
If the disk had twice the radius and twice the mass
The new moment of inertia
![I'=\dfrac{1}{2}\times2M\times(2R)^2](https://tex.z-dn.net/?f=I%27%3D%5Cdfrac%7B1%7D%7B2%7D%5Ctimes2M%5Ctimes%282R%29%5E2)
![I'=8I](https://tex.z-dn.net/?f=I%27%3D8I)
We know,
The torque is
![\tau=F\times R](https://tex.z-dn.net/?f=%5Ctau%3DF%5Ctimes%20R)
We need to calculate the initial rotation acceleration
Using formula of acceleration
![\alpha=\dfrac{\tau}{I}](https://tex.z-dn.net/?f=%5Calpha%3D%5Cdfrac%7B%5Ctau%7D%7BI%7D)
Put the value in to the formula
![\alpha=\dfrac{F\times R}{\dfrac{1}{2}MR^2}](https://tex.z-dn.net/?f=%5Calpha%3D%5Cdfrac%7BF%5Ctimes%20R%7D%7B%5Cdfrac%7B1%7D%7B2%7DMR%5E2%7D)
![\alpha=\dfrac{2F}{MR}](https://tex.z-dn.net/?f=%5Calpha%3D%5Cdfrac%7B2F%7D%7BMR%7D)
We need to calculate the new rotation acceleration
Using formula of acceleration
![\alpha'=\dfrac{\tau}{I'}](https://tex.z-dn.net/?f=%5Calpha%27%3D%5Cdfrac%7B%5Ctau%7D%7BI%27%7D)
Put the value in to the formula
![\alpha=\dfrac{F\times R}{8\times\dfrac{1}{2}MR^2}](https://tex.z-dn.net/?f=%5Calpha%3D%5Cdfrac%7BF%5Ctimes%20R%7D%7B8%5Ctimes%5Cdfrac%7B1%7D%7B2%7DMR%5E2%7D)
![\alpha=\dfrac{2F}{8MR}](https://tex.z-dn.net/?f=%5Calpha%3D%5Cdfrac%7B2F%7D%7B8MR%7D)
![\alpha=\dfrac{\alpha}{8}](https://tex.z-dn.net/?f=%5Calpha%3D%5Cdfrac%7B%5Calpha%7D%7B8%7D)
Rotation speed is same.
We need to calculate the time
Using formula angular velocity
![\Omega=\omega'](https://tex.z-dn.net/?f=%5COmega%3D%5Comega%27)
![\alpha\time t=\alpha'\times t'](https://tex.z-dn.net/?f=%5Calpha%5Ctime%20t%3D%5Calpha%27%5Ctimes%20t%27)
Put the value into the formula
![\alpha\times120=\dfrac{\alpha}{8}\times t'](https://tex.z-dn.net/?f=%5Calpha%5Ctimes120%3D%5Cdfrac%7B%5Calpha%7D%7B8%7D%5Ctimes%20t%27)
![t'=960\ sec](https://tex.z-dn.net/?f=t%27%3D960%5C%20sec)
![t'=16\ min](https://tex.z-dn.net/?f=t%27%3D16%5C%20min)
Hence, The time is 16 min.