how do you find theta in this equation? please help?

Question

mgsin(theta) = ma
the m's cancel out and when i find sin of theta i get 0.1224, but how do you get theta alone?

Answer 1

Use the inverse sin function:

m*g*sin(theta) = m*a

g*sin(theta) = a

sin(theta) = a/ g

theta = inv.sin(a/g)

There should be values for inverse sin in most calculus books I believe and most calculators as well. It looks like a SIN function on the calculator except there is a -1 next to the N.

Answer 2

If you get to the point of having g*sin(theta) = a, you can then say sin(theta) = a/g, and then theta = arcsin(a/g). Arcsine, often written as arcsin or sin^-1, is the inverse of the sine operation, and it's the only way to solve an equation in this form.

Answer 3

You have to take the inverse sine of both sides to get theta alone.
mgsin(theta)=ma
gsin(theta)=a; m is approximately 9.81 I believe
sin-1(sin(theta))=sin-1(a)
theta=sin-1(a)

You can use your calculator to get the answer.

Answer 4

You could do one of the following:
1 - look it up in a table of angles versus sin values
2 - look it up on a scientific calculator
3 - use a slide rule

Answer 5

sin(theta) = 0.1224
=> theta = arcsin 0.1224 = 7.03 degree