Answer:
A flower emits only visible light
A flower reflects much of the light that hits it
Answer:
Explanation:
Stiffness of spring k equal to 4 lb/ft.
Unstretched length of the spring L is equal to 0.5 feet.
Weight of the collar W is 15lb
Radius of curvature of curve guide is 1 feet
length of vertical rod is 1.5 feet
Initial speed of collar when released from rest at A is 0 feet per seconds
use the energy conservation equation

Estimate the potential energy , component as position B as below

Estimate the kinetic energy , component as position A as below

Estimate the kinetic energy , component as position B as below

Substitute 20.5lb- ft for 
0.5lb-ft for 
0lb -ft for 


= 16.05ft/sec
Answer:
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Answer: h = 3.34 m
Explanation:
If the hat is thrown straight up, then at its highest point it has no motion and no kinetic energy. All energy is potential energy
PE = mgh
h = PE/mg = 4.92 / (0.150(9.81)) = 3.34352... ≈3.34 m
Answer:


Explanation:
Electrostatic Force
It's the force that appears between two electrical charges q1 q2 when they are placed at a certain distance d. The force can be computed by using the Coulomb's law:

We have an arrangement of 4 charges as shown in the image below. We need to calculate the total force exerted on the charge 2Q by the other 3 charges. The free body diagram is also shown in the second image provided. The total force on 2Q is the vectorial sum of F1, F2, and F3. All the forces are repulsive, since all the charges have the same sign. Let's compute each force as follows:


The distance between 3Q and 2Q is the diagonal of the rectagle of length l:

The force F3 is

Each force must be expressed as vectors. F1 is pointed to the right direction, thus its vertical components is zero

F2 is pointed upwards and its horizontal component is zero

F3 has two components because it forms an angle of 45° respect to the horizontal, thus


Now we compute the total force




Now we compute the magnitude

The direction of the total force is given by

