<span>Answer:
Using 1/f = 1/d' + 1/d ...(where d' object distance and d is image distance)
1/4 = 1/7 + 1/d
1/4 - 1/7 = 1/d
3/28 = 1/d
d = 28/3
d = 9.33 cm</span>
A = .3*g = 2.94 m/s²
<span>t = v/a = 9/2.94 = 3.061 sec </span>
<span>W = E/t = ½mv²/t = ½*40*9²/3.061 = 529.2 watts</span>
Answer:
30°
Explanation:
According to the second law of reflection, it States that the angle of incidence i is equal to the angle of reflection r.
The angle of incidence is known to be the angle between the incident ray and the normal.
The Angle of reflection is the angle between the reflected ray and the normal.
This normal ray is a ray that is perpendicular to the surface.
According to the question, if the beam of light is reflected off the surface and its angle of incidence is 30°, its angle of reflection will also be 30° i.e i=r = 30°
Answer:
5.82812 rad/s
Explanation:
L = Length of meter stick = 1 m = 100 cm
= The center of mass of the stick = 
= Angular velocity
Moment of inertia of the system is given by

As the energy in the system is conserved

The maximum angular velocity is 5.82812 rad/s
A textbook would hit the ground first
Factors:
-Textbook weighs most
-Pillow is flat and fluffy not very aerodynamic) also is very light
-Paper airplane will glide to the ground do to its wings and will hit the ground last