A nearsighted person has a far point that is 4.2 m from his eyes. What power contact lenses must he wear to allow him to focus on distant mountains?
A) 0.24 diopters
B) -0.36 diopters
C) -0.48 diopters
D) -0.24 diopters
E) 0.48 diopters
D
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Jennifer bungee-jumps from a bridge (event A). Jennifer’s bungee cord is perfectly elastic, so she bounces exactly back up to the bridge and lands on her feet (event B). The time between these events is measured by Jennifer’s watch, a stopwatch held by Jennifer’s friend, Rob, who is standing on the bridge, and by two passengers (one present at event A and one present at event B) who are riding on a train traveling at a constant velocity across the bridge at the time (the passengers have synchronized watches and compare readings later). Assuming the earth’s frame is inertial, who measures
(a) the longest time interval between these events? A. Jennifer B. Rob C. The train passengers
As originally stated, the Copernican model did no better job of predicting planetary behavior than did the Ptolemaic one
Indicate whether the statement is true or false
An object of mass 2.00 kg is held at a position A, a vertical height of 20.0 m above the ground. Point B is 8.00 m directly below A. Neglect air resistance and use g = 10.0 m/s2
(a) What is the speed of the object at position B when it falls from position A? (b) What is the speed of the object just before it touches the ground? (c) What is the ratio of the total energy of the object at position A to position B?
A block lies on a horizontal frictionless surface. A horizontal force of 100 N is applied to the block giving rise to an acceleration of 3.0 m/s2. (a) Determine the mass of the block
(b) Calculate the distance the block will travel if the force is applied for 10 s. (c) Calculate the speed of the block after the force has been applied for 10 s.