physics
posted by galileo .
Suppose that the displacement of a particle is related to time according to the expression delta x = ct^3. What are the SI units of the proportionality constant c?
My answer: delta x = ct^3
m = c s^3 (s: seconds)
m/s^3= c
The SI units for c: m/s^3 correct?
2) Determine if dimensions are correct:
K = 1/2mv2
kgm^2/s^2 = kgm^2/s^2 * 1/2
kgm^2/s^2 = kgm^2/2s^2
The above equation is not dimensionally correct. However, I am somewhat confused as this is suppose to be the kinetic energy formula, and I just found that it is not dimensionally correct. Did I go wrong somewhere?
3) The mass of the Earth is 5.98E24 kg and its average density is 5.520kg/m^3. Assuming the Earth is spherical, find (a)its volume in m^3, (b) its radius in m, and (c) its radius in mi (miles).
My half solution:
Although I know the volume of a sphere is 4/3 pi r^3, here it throws me off.
I can find the volume simply by:
5,520kg = m^3/5.98E24kg; cross multiply and kg cancel(?) leaving me with V(earth)= 2.15E6 m^3(?)
Here, I'm lost about finding the radius in m and radius in miles. Should I use formula 4/3 pi r^3?
Thank you so much.
<<I'm lost about finding the radius in m and radius in miles. Should I use formula 4/3 pi r^3?
>>
Since you know V, rearrange that equation to get
r = (cube root of)[3 V/(4 pi)]
To convert meters to miles, divide by 1609.3 meters/mile
<<I'm lost about finding the radius in m and radius in miles. Should I use formula 4/3 pi r^3?
>>
Since you know V, rearrange that equation to get
r = (cube root of)[3 V/(4 pi)]
To convert meters to miles, divide by 1609.3 meters/mile
(1)Your answer is correct
(2) 1 kg m^2/s^2 is the same as 1 Joule, or 1 Newtonmeter. The KE equation IS dimensionally correct
Respond to this Question
Similar Questions

Physics
please check if these are right 1. Which of the following is the equation for average velocity? 
Chemistry
Clapeyron equation: dp/dT = ΔS / ΔV My textbook says, for fusion/melting reactions: dp/dT = ΔH / (T ΔV) this implies that T * ΔS = ΔH. I know T * ΔS = q and at constant pressure, that equals … 
Physics
1. If the change in position delta(x) is related to velocity v (w/ units of m/s) in the equation delta(x)=Av, the constant A has which dimension? 
physics
The problem is: You apply your brakes to stop for a traffic light, and you come to a stop in a distance of 35 meters. How much time did it take you to stop? 
physics
The problem is: You apply your brakes to stop for a traffic light, and you come to a stop in a distance of 35 meters. How much time did it take you to stop? 
calculus
correct me if I'm wrong please. 1. What is the value of Lim 2x+3/4x5 when x>00 (infinity? 
physics
a 2.0 kg particle is given a displacement (delta)r= 2.0i+3.0j (m). During this displacement, a constant force, F=2.0i5j (N) acts at the particle. find the work done by the force for this displacement. 
Chemistry(Please check answers)
1) For a reaction delta Go is more negative than delta Ho. What does this mean? 
Chemistry
Please explain. The enthalpy changes for two different hydrogenation reactions of C2H2 are: C2H2+H2>C2H4 Delta H 1 C2H2+2H2>C2H6 Delta H 2 Which expression represents the enthalpy change for the reaction below? 
CHEMISTRY
Please explain. The enthalpy changes for two different hydrogenation reactions of C2H2 are: C2H2+H2>C2H4 Delta H 1 C2H2+2H2>C2H6 Delta H 2 Which expression represents the enthalpy change for the reaction below?