2) Power of the lens is -40, its focal length is
b) -40m c)-0.25m
a) 4m
d) -25m

=force × distance a. work b. velocity c. pressure d. momentum

How many times did thomas edison mess up the light bulb

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.