An upright object 3 cm high is placed to the left of a lens of focal length 40 cm. An inverted
image is formed 60 cm from the lens.
How far from the lens is the object located? What is the height of the image? Trace at
least two rays from th
A 0.25-kg mass attached to a spring of force constant 30 N/m is free to oscillate on a horizontal,
frictionless surface. The system is in its equilibrium position when an enthusiastic physics
student (you, for instance) pushes the mass to the ri
v max = A" #
= v max
= (2.0 m s)
30 N m
E = K + U = mv 2 + kx 2 = kA 2 "
30 N m
A # x2) =
(0.18m) # (#0.1m) = 1.67 m s
x ( t ) = "Asin(#t )
v ( t ) = "
1 1 1
do d i f
1 1 1
= " =
# do = 120cm
do f di 40cm 60cm
Thus, the object is located 120 cm to the left of the first lens.
= 0.5 = i "
hi = 0.5ho = (0.5)( 3cm) = 1.5cm
The height of the image is 1.5 c
The crossing signal is the (stationary) source, and you are the (moving) observer. The higher
frequency is heard when the observer is moving toward the source, while the lower frequency is
heard when the observer is moving away from the source.
Riding on a train, you detect sound from a crossing signal in the vicinity. As the train approaches
the crossing, the frequency you hear is 1800 Hz. After the train passes the crossing, the
frequency you hear is 1500 Hz. At what speed is the train mo