Answer:
D.
Explanation:
Red light has wavelengths around 620 to 750 nm.
The answer is ...
28 km per hour
The net force needed to lift a full grocery sack uniformly is 32.115 N.
<h3>What is Net force?</h3>
When two or more forces are acting on the system of objects, then the to attain equilibrium, net force must be zero.
Given the weight of sack W = 210N and the acceleration a = 1.5m/s².
The mass of the sack will be
m = Weight / acceleration due to gravity
m = 210 N/9.81 m/s²
m = 21.41 kg
Using Newton's second law, the net force will be
F = mass x acceleration
F= 21.41 x 1.5
F = 32.115 N
Thus, the net force is 32.115 N.
Learn more about net force.
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To solve this problem we will use the trigonometric concepts to find the distance h, which will allow us to find the speed of Jeff and that will finally be the variable that will indicate the total tension, since it is the variable of the centrifugal Force given in the vine at the lowest poing of the swing.
From the image:
When Jeff reaches his lowest point his potential energy is converted to kinetic energy
Tension in the string at the lowest point is sum of weight of Jeff and the his centripetal force
Therefore the tension in the vine at the lowest point of the swing is 842.49N