1 2.1.3.4.1.5.1.6
You stand on a bridge above a river and drop a rock into the water below from a height of 35 m.
(Assume no air resistance.)
a. What is the acceleration of the rock as it falls? (2 points)
b. How long does it take to hit the water? (4 points)
c. How much more time would it take if instead of dropping the rock straight down, you threw it
horizontally with a speed of 20 m/s? (4 points)
d. You throw another rock at an angle of 65° above the horizontal with a speed of 20 m/s. What
are the x- and y-components of the rock's speed? (3 points)
1
e How long does it take the rock to reach its maximum height? (2 points)

Why does the input force have to be greater than the force needed to lift the bale?

Achild throws a ball with an initial speed of 8.00 m/s at an angle of 40.0° above the horizontal. the ball leaves her hand 1.00 m above the ground. how long is the ball in flight before it hits the ground?

The particle in a two-dimensional well is a useful model for the motion of electrons around the indole ring (3), the conjugated cycle found in the side chain of tryptophan. we may regard indole as a rectangle with sides of length 280 pm and 450 pm, with 10 electrons in the conjugated p system. as in case study 9.1, we assume that in the ground state of the molecule each quantized level is occupied by two electrons. (a) calculate the energy of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels. 9.27 electrons around the porphine ring (4), the conjugated macrocycle that forms the structural basis of the heme group and the chlorophylls. we may treat the group as a circular ring of radius 440 pm, with 20 electrons in the conjugated system moving along the perimeter of the ring. as in exercise 9.26, assume that in the ground state of the molecule quantized each level is occupied by two electrons. (a) calculate the energy and angular momentum of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels.