W =

[minnsy229]

Combine the following two equations to give an equation for W which does not involve g.

Equation (1): W = mg
Equation (2): s = 1/2gt^2
Give your answer in the simplest form and without brackets. Use the '/' key and/or the superscript box to format your answer, as appropriate.

W =

 

[minnsy229]

Hi

so it should be 1/2mt^2 ????

1: get g from equation (2)
2: substitute in equation (1)

 

[tkhunny]

Better try that again. What did you get for 'g' out of the second equation?

Where did 's' go?

 

[srmichael]

so it should be 1/2mt^2 ????

No. What Denis meant is use equation 2 to solve for g and then substitute that formula into equation 1.

\(\displaystyle \displaystyle s=\frac{1}{2}gt^2\)

\(\displaystyle \displaystyle 2s=gt^2\)

\(\displaystyle \displaystyle \frac{2s}{t^2}=g\)

Now, substitute this formula for g into the first equation.

 

[minnsy229]

mmmmm

so, 2ms/t^2 ?

No. What Denis meant is use equation 2 to solve for g and then substitute that formula into equation 1.

\(\displaystyle \displaystyle s=\frac{1}{2}gt^2\)

\(\displaystyle \displaystyle 2s=gt^2\)

\(\displaystyle \displaystyle \frac{2s}{t^2}=g\)

Now, substitute this formula for g into the first equation.

 

[srmichael]

so, 2ms/t^2 ?

Yup!