Answer:
20.4m
Explanation:
72kmhr(1000mkm)(hr3600sec)=20ms
Use principles of conservation of energy.
The initial kinetic energy of the car is equal to the work done by friction during braking:
KE=Wfric
12mv2=(Ffric)d
but the force of friction = weight of the car = mg
12mv2=mgd
mass cancels in both terms, which tells us the answer is independent of mass
12v2=gd
12202=(9.81)d
d=20.4m
Note that the correct answer should actually be 20. m with only 2 significant figure accuracy since 72 km/hr only has 2 sig fig accuracy.
Answer:
In a biology experiment the number of yeast cells is determined after 24 hours of culture at different temperatures. a) Identify the independent and dependent variables in the experiment. b) Draw the graph of the
Explanation:
Answer:
90 W
Explanation:
The power of the light bulb is given by:
![P=VI](https://tex.z-dn.net/?f=P%3DVI)
where
V is the voltage of the bulb
I is the current through the bulb
In this problem,
V = 120 V
I = 0.75 A
Substituting into the equation,
![P=(120)(0.75)=90 W](https://tex.z-dn.net/?f=P%3D%28120%29%280.75%29%3D90%20W)
1) Star from the definition of power:
P = work/ time = W / Δt
We know that work is given by force times displacement:
W = F · Δd
Substituting in our formula:
P = F · Δd / <span>Δt
But we know by definition that </span>Δd / <span>Δt = velocity, therefore we can write:
</span>P = F · v
which is the alternative formula saying that Power is equal to Force times Velocity
2) No, it is not a violation of the Law of conservation of energy because as the spring slows down, the kinetic energy is transformed into potential energy and their sum stays constant.
The correct answer is: Option (3) 9.8 N/kg
Explanation:
According to Newton's Law of Gravitation:
--- (1)
Where G = Gravitational constant = 6.67408 × 10⁻¹¹ m³ kg⁻¹ s⁻²
m = Mass of the body = 2 kg
M = Mass of the Earth = 5.972 × 10²⁴ kg
R = Distance of the object from the center of the Earth = Radius of the Earth + Object's distance from the surface of the Earth = (6371 * 10³) + 3.0 = 6371003 m
Plug in the values in (1):
(1)=> ![F_g = \frac{6.67408 * 10^{-11} * 2 * 5.972*10^{24}}{(6371003)^2} = 19.63](https://tex.z-dn.net/?f=%20F_g%20%3D%20%5Cfrac%7B6.67408%20%2A%2010%5E%7B-11%7D%20%2A%202%20%2A%205.972%2A10%5E%7B24%7D%7D%7B%286371003%29%5E2%7D%20%3D%2019.63%20)
Now that we have force strength at the location, we can use:
Force = mass * gravitational-field-strength
Plug in the values:
19.63 = 2.0 * gravitational-field-strength
gravitational-field-strength = 19.63/2 = 9.82 N/kg
Hence the correct answer is Option (3) 9.8 N/kg