An object weighting 300 N is suspended by means of two cords. (There is a cord on the ceiling with is at 45 degrees. The second cord is attached to the wall and is horizontal. These two cords are attached to a cord which has the 300N object on it.) The tension in the horizontal cord is

a)0 N
b)150 N
c)210 N
d)300 N
e)400 N

would I use 300sin 90 which equals 300N?

No. If T is the horizontal cord tension, and T' is the vertical cord tension
T' sin 45 = 300 N
T' cos 45 = T
Solve for T, eliminating T'. Remember that sin 45 = cos 45

T = 300 N / sqrt(2) = 210 N

To solve for the tension in the horizontal cord, we will use the given information and the equations:

T' sin 45 = 300 N (equation 1)
T' cos 45 = T (equation 2)

First, we will solve equation 1 for T':

T' sin 45 = 300 N
T' = 300 N / sin 45

Using a calculator, we find that sin 45 is approximately 0.7071.

T' = 300 N / 0.7071
T' ≈ 424.26 N

Next, we will substitute the value of T' into equation 2 to solve for T:

T' cos 45 = T
424.26 N * cos 45 = T

Using a calculator, we find that cos 45 is also approximately 0.7071.

T ≈ 424.26 N * 0.7071
T ≈ 300 N

Therefore, the tension in the horizontal cord is approximately 300 N. Thus, the correct answer is option d) 300 N.

To find the tension in the horizontal cord, we can use the given information:

T' sin 45 = 300 N

This equation represents the vertical component of the tension in the vertical cord. Since the object is in equilibrium, the vertical component of the tension balances the weight of the object.

Now, let's solve for T', the tension in the vertical cord:

T' = 300 N / sin 45
T' = 300 N / 0.707

Next, we can find the horizontal component of the tension using trigonometry:

T' cos 45 = T

Since sin 45 = cos 45, we can simplify the equation to:

T' = T

Now, substitute the value of T' that we found earlier:

T = 300 N / 0.707

Calculating this value, we get:

T ≈ 423.81 N

Therefore, the tension in the horizontal cord is approximately 423.81 N. Since none of the answer choices match this value exactly, it seems there might be a mistake or rounding error in the problem or answer choices.