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)

12 drag each label to the correct category. decide whether each statement describes mass or weight. measured in newtons measured in kilograms does not change when gravity changes === a gravitational force changes when gravity changes the amount of matter in something mass weight

Search coils and credit cards. one practical way to measure magnetic field strength uses a small, closely wound coil called a search coil. the coil is initially held with its plane perpendicular to a magnetic field. the coil is then either quickly rotated a quarter-turn about a diameter or quickly pulled out of the field. (a) derive the equation relating the total charge q that flows through a search coil to the magnetic-field magnitude b. the search coil has n turns, each with area a, and the flux through the coil is decreased from its initial maximum value to zero in a time ∆t. the resistance of the coil is r, and the total charge is q = i∆t, where i is the average current induced by the change in flux. (b) in a credit card reader, the magnetic strip on the back of a credit card is rapidly “swiped” past a coil within the reader. explain, using the same ideas that underlie the operation of a search coil, how the reader can decode the information stored in the pattern of magnetization on the strip. (c) is it necessary that the credit card be “swiped” through the reader at exactly the right speed? why or why not?

Which best describes how fluids change as they travel through different portions of the convection currents? they change to solids at the outer portion of the convection currents. they change to solids at the inner portion of the convection currents. they become more dense at the outer portion of the convection currents. they become more dense at the inner portion of the convection currents