F=MA
F=(8 kg)(9.8 m/s)
F= 78.4 N
W=FD
W=(78.4 N)(7 m)
W=548.8 J
How this helps
They differ from each other<span> in wavelength. Wavelength is the distance between </span>one wave<span> crest to the next. </span>Waves<span> in the </span>electromagnetic<span> spectrum vary in size from very long radio </span>waves<span> the size of buildings, to very short gamma-rays smaller </span>than<span> the size of the nucleus of an atom.</span>
Explanation:
The given data is as follows.
Angular velocity (
) = 2.23 rps
Distance from the center (R) = 0.379 m
First, we will convert revolutions per second into radian per second as follows.
= 2.23 revolutions per second
=
= 14.01 rad/s
Now, tangential speed will be calculated as follows.
Tangential speed, v =
= 0.379 x 14.01
= 5.31 m/s
Thus, we can conclude that the tack's tangential speed is 5.31 m/s.
Explanation:
Image distance, v = -17 cm (-ve for virtual image)
Radius of curvature of concave mirror, R = 39 cm
Focal length, f = -19.5 cm (-ve for a concave mirror)
(a) Using mirror's formula as :


u = 132.6 cm
So, the object is placed 132.6 cm in front of the mirror.
(b) Magnification of the mirror, 

m = -0.128
Hence, this is the required solution.